Search Tools
Showing all 285 tools
2048 Game
Free 2048 sliding tile puzzle game — combine matching numbered tiles on a 4x4 grid to reach the 2048 tile. Play in your browser with keyboard arrow keys or touch swipe on mobile.
3D Print Time Calculator
Free 3D Print Time Calculator — estimate FDM and resin (SLA/DLP) print duration, filament usage, spool consumption, and total material + electricity cost for any 3D printing project.
3D Printing Filament Calculator
Free 3D Printing Filament Calculator — estimate filament cost, print cost breakdown, electricity, labor, depreciation, and remaining filament on any spool. Supports PLA, PETG, ABS, ASA, TPU, Nylon, PC, and more.
500 Rule Calculator
Free 500 Rule Calculator for astrophotography — instantly find the maximum shutter speed to avoid star trails using the 500 rule, NPF rule, and all rule variants for any camera sensor.
A/B Test Sample Size Calculator
Free A/B Test Sample Size Calculator — determine the minimum sample size per variation needed to detect a statistically significant result, estimate test duration, and analyze post-test significance with p-value, z-score, and confidence intervals.
A1C Calculator
Free A1C calculator to convert between HbA1c percentage and estimated average glucose (eAG). Supports bidirectional conversion, IFCC mmol/mol, mg/dL and mmol/L units, and ADA risk classification.
ABI Calculator
Free ABI Calculator to compute the Ankle-Brachial Index for both legs. Detect peripheral artery disease (PAD) risk with clinical six-tier interpretation and visual severity gauge.
ACFT Calculator (Army Combat Fitness Test)
Free ACFT and AFT score calculator. Calculate your Army Combat Fitness Test score for all 6 events with gender and age-group adjusted scoring, performance tiers, and training tips.
ACR Calculator
Free ACR calculator for albumin-to-creatinine ratio. Get KDIGO albuminuria classification (A1/A2/A3), CKD risk matrix, nephrotic range flag, and clinical interpretation.
ACT Score Calculator
Free ACT Score Calculator — calculate your ACT composite score, section percentile ranks, SAT equivalent, STEM score, and college tier benchmarks. Supports 2025 and pre-2025 formats.
AFT Calculator
Free Army Fitness Test (AFT) calculator with 2025 scoring tables. Calculate your score for all 5 AFT events (MDL, HRP, SDC, PLK, 2MR) with age and gender-normed results, pass/fail status, and performance tier.
Age Calculator
Free age calculator to instantly calculate your age in years, months, days, hours, and more. Find out when your next birthday is!
AHI Calculator
Free AHI calculator for sleep apnea. Calculate your Apnea-Hypopnea Index, severity classification, and treatment recommendations based on AASM guidelines.
Algebra Calculator
Free algebra calculator — solve linear and quadratic equations, simplify expressions, factor polynomials, expand expressions, and solve 2x2 systems of equations with step-by-step solutions.
Alimony Calculator
Free Alimony (Spousal Support) Calculator — estimate monthly and annual alimony payments using 10 state-specific formulas including AAML, California, Illinois, Texas, Kansas, Massachusetts, Pennsylvania, Arizona, Virginia, and the General one-third rule.
Amortization Calculator
Free loan amortization calculator with extra payments, full amortization schedule, bi-weekly comparison, and mortgage PITI mode. See exactly how every payment splits between principal and interest.
Amplifier Power Calculator
Free Amplifier Power Calculator — solve for output power, RMS/peak/peak-to-peak voltage, and current using Ohm's Law. Size amplifiers acoustically with SPL-based power requirements, headroom analysis, and heat dissipation estimates for Class A, AB, and D amplifiers.
ANC Calculator
Free ANC calculator for absolute neutrophil count. Get NCI CTCAE grading, neutropenia severity classification, febrile neutropenia alerts, and clinical guidance for oncology patients.
Angle Converter
Free online Angle Converter — instantly convert degrees, radians, gradians, minutes of arc, seconds of arc, revolutions, quadrants, sextants, mils, and more. Includes DMS input, visual angle diagram, and all-units table.
Antenna Length Calculator
Free antenna length calculator for dipole, quarter-wave vertical, full-wave loop, inverted vee, 5/8-wave vertical, and 3-element Yagi antennas. Get exact lengths in both feet and meters instantly.
APFT Calculator
Free Army Physical Fitness Test (APFT) score calculator. Get instant push-up, sit-up, and 2-mile run scores by age group and gender with pass/fail results.
Arduino PWM Frequency Calculator
Free Arduino Pulse-Width Modulation (PWM) frequency calculator. Configure timer, prescaler, mode, and duty cycle — generates ready-to-paste Arduino C++ register setup code with waveform preview.
Area Converter
Free online Area Converter — instantly convert between square meters, square feet, acres, hectares, square kilometers, square miles, and 9 other area units with a real-time all-units table and real-world size comparisons.
ARR Calculator
Free Annual Recurring Revenue (ARR) calculator for SaaS businesses. Calculate ARR from MRR, customer counts, pricing tiers, or ARR components. Includes waterfall bridge, 12-month projections, NRR, CLV, and valuation multiples.
ASCII Table
Free ASCII Table tool — format raw text data into beautiful ASCII art tables with 10+ border styles, and browse the complete ASCII character reference chart (0–127) with Dec, Hex, Oct, Bin, HTML, and character name columns.
Astrophotography Exposure Calculator
Free Astrophotography Exposure Calculator — compute the maximum untracked shutter speed using the 500 Rule, 400 Rule, 300 Rule, NPF Rule, and Plate Scale method, plus SNR-based sub-exposure planning for tracked deep-sky imaging.
Average Calculator
Free Average Calculator — compute the arithmetic mean, median, mode, range, standard deviation, geometric mean, harmonic mean, and more from any set of numbers. Supports simple and weighted average modes.
AWG Wire Gauge Calculator
Free American Wire Gauge (AWG) calculator — look up wire diameter, cross-sectional area, and resistance; size wires by current and voltage drop; convert diameters to AWG; and calculate equivalent gauge for parallel wires.
AWG Wire Size Table
Free American Wire Gauge (AWG) wire size reference table and calculator. Look up wire diameter, cross-sectional area, resistance, ampacity, skin depth, and breaking force for AWG 4/0 through AWG 40. Supports copper, aluminum, and 6 other materials.
Baby Due Date Calculator
Free baby due date calculator with multiple formulas (Naegele's Rule, Mittendorf-Williams, Parikh's Formula), IVF support, trimester breakdown, zodiac signs, birthstones, prenatal screening schedule, and pregnancy progress charts.
Baby Feeding Schedule Calculator
Free Baby Feeding Schedule Calculator — calculate your baby's daily milk intake, per-feeding amounts, and generate a complete 24-hour feeding timetable with night-feeding indicators. Supports breast milk, formula, and mixed feeding.
Baby Formula Calculator
Free Baby Formula Calculator — estimate how much formula your infant needs per day and per feeding based on weight, age, and feedings per day. Supports metric and imperial units.
Baby Growth Percentile Calculator
Free Baby Growth Percentile Calculator using WHO (0–24 months) and CDC (24–36 months) growth charts. Get weight-for-age, length/height-for-age, head circumference, and weight-for-length percentiles with Z-scores and clinical interpretations.
Baby Percentile Calculator
Free baby growth percentile calculator using WHO and CDC standards. Calculate weight, length, and head circumference percentiles for infants and toddlers 0–36 months.
Baby Sleep Schedule Calculator
Free Baby Sleep Schedule Calculator — generate a personalized age-appropriate daily sleep schedule with wake windows, nap times, and bedtime based on your baby's age (0–36 months).
Baby Vaccination Schedule
Free personalized baby vaccination schedule tool based on the CDC 2025 recommended immunization schedule. Enter your child's date of birth to see exact appointment dates, track completed vaccines, and identify upcoming and overdue doses.
BAC Calculator
Free blood alcohol content (BAC) calculator using the Widmark formula. Estimate your BAC based on drinks consumed, body weight, gender, and time elapsed.
BAH Calculator
Free Basic Allowance for Housing (BAH) calculator for 2026. Look up your monthly and annual BAH by pay grade, duty station ZIP code, and dependency status. Covers all 35 military pay grades.
BAI Calculator
Free Body Adiposity Index (BAI) calculator. Estimate body fat percentage using only hip circumference and height — no scale required.
BAS Calculator
Free Basic Allowance for Subsistence (BAS) calculator for U.S. military service members. Calculate your monthly and annual tax-free food allowance, prorate for partial months, and compare enlisted vs. officer rates from 2019 to 2025.
Battery Capacity Calculator
Free battery capacity calculator for runtime, charge time, and energy storage. Calculate how long your battery will last, how long it takes to charge, and design series/parallel battery banks.
Battery Runtime Calculator
Free Battery Runtime Calculator — estimate how long your battery will last under any load. Supports Standard (Ah/Wh), Peukert lead-acid, and IoT duty-cycle modes with chemistry presets and scenario comparison.
BBT Calculator
Free BBT calculator and fertility charting tool. Track basal body temperature, detect ovulation, calculate coverline, and identify your fertile window.
BED Calculator
Free Biologically Effective Dose (BED) calculator. Compute BED and EQD2 using the Linear-Quadratic model with tissue-specific alpha/beta ratios, protracted delivery correction, boost dose modules, and multi-schema fractionation comparison.
BEE Calculator
Free BEE calculator using Harris-Benedict, Mifflin-St Jeor, Katch-McArdle, and Schofield equations. Includes clinical stress factors for TPN and tube-feeding calculations.
Bike Frame Size Calculator
Free Bike Frame Size Calculator — find your perfect bicycle frame size using height and inseam length for road, mountain, hybrid, and kids bikes.
Bike Size Calculator
Free Bike Size Calculator — find the right bicycle frame size for road, mountain, city, BMX, and kids bikes using your height and inseam measurements.
Bitcoin Mining Calculator
Free Bitcoin Mining Calculator — estimate your daily, monthly, and yearly BTC earnings and USD profits based on your hardware hashrate, power consumption, electricity cost, and current network difficulty.
Blood Pressure Calculator
Check your blood pressure category using AHA/ACC 2017 guidelines. Get your BP classification, MAP, pulse pressure, risk level, and personalized health recommendations.
Blood Type Calculator
Predict your child's possible blood types based on both parents' ABO and Rh factor genetics. Includes probability percentages, Punnett square, compatibility chart, and reverse lookup.
BMI Calculator
Calculate your Body Mass Index and check if you're in a healthy weight range
BMR Calculator
Free BMR (Basal Metabolic Rate) calculator to estimate the number of calories your body burns at rest. Uses both Mifflin-St Jeor and Harris-Benedict formulas with activity level adjustment for TDEE.
Body Fat Calculator
Free body fat calculator using the US Navy method and BMI-based estimation. Calculate your body fat percentage, fat mass, lean mass, and body fat category.
Body Type Calculator
Free body type calculator using quiz, measurements, and Heath-Carter somatotype method. Discover if you are an ectomorph, mesomorph, or endomorph with personalized training and nutrition recommendations.
BPM to MS Converter
Free Beats Per Minute (BPM) to milliseconds converter for music producers, DJs, and sound designers. Instantly calculate delay times, reverb pre-delays, and LFO rates for all note values including whole, half, quarter, eighth, sixteenth, 32nd, and 64th notes — with dotted and triplet variations.
BRI Calculator
Free BRI Calculator using the Thomas et al. formula. Calculate your Body Roundness Index, health risk tier, waist-to-height ratio, body eccentricity, BMI, and population percentile instantly.
BSA Calculator
Free body surface area calculator using all 8 clinical formulas (Mosteller, Du Bois, Haycock, Gehan-George, Boyd, Fujimoto, Takahira, Schlich). Includes medication dose calculator, cardiac index module, and burn fluid resuscitation.
Bubble Shooter Game
Free classic Bubble Shooter game — match 3 or more same-color bubbles to pop them, avoid letting the grid reach the bottom, and beat your high score. No download required.
Budget Calculator
Free monthly Budget Calculator — plan your income and expenses across housing, transportation, food, healthcare, savings, debt, and personal categories. Get instant surplus/deficit, savings rate, 50/30/20 rule analysis, category benchmarks, and CSV export.
CAC Calculator
Free Customer Acquisition Cost (CAC) calculator — compute how much it costs to acquire each new customer, measure LTV:CAC ratio, calculate payback period, and compare your performance against industry benchmarks for SaaS, e-commerce, and more.
Calorie Calculator
Free calorie calculator to estimate your daily calorie needs for weight loss, maintenance, or weight gain based on your age, gender, height, weight, and activity level.
Calorie Deficit Calculator
Free calorie deficit calculator. Calculate your BMR, TDEE, daily calorie target, macros, and weight loss timeline. Supports Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.
Calories Burned Running Calculator
Free calories burned running calculator using MET-based formulas from the Compendium of Physical Activities. Calculate total calories, fat burned, pace-based rates, and weekly projections.
Calories Burned Walking Calculator
Free walking calorie calculator. Enter your weight, walking speed, duration, distance, or steps and get instant calorie burn results including fat loss, distance, step count, and weekly projections.
Camp Stove Fuel Calculator
Free camp stove fuel calculator for backpacking and camping trips. Estimate total fuel needed in grams and ounces, get canister recommendations, compare sizes, and check partial canisters.
Car Lease Calculator
Free Car Lease Calculator — compute your monthly payment, total lease cost, cash due at signing, and cost per mile using the industry-standard money factor formula.
Carbohydrate Calculator
Free carbohydrate calculator that uses your age, sex, height, weight, activity level, and goal to calculate your optimal daily carb intake in grams using the Mifflin-St Jeor formula.
Carbon Footprint Calculator
Free Carbon Footprint Calculator — estimate your annual CO₂ emissions from transportation, home energy, diet, and shopping. Compare to global averages, see trees needed to offset, and get personalized reduction tips.
CBM Calculator
Free Cubic Meter (CBM) calculator for shipping — calculate total volume, container fit for 20ft/40ft/40HC, volumetric weight for air and sea freight, chargeable weight, and LCL vs FCL recommendations.
CCI Calculator
Free Charlson Comorbidity Index calculator. Assess comorbidity burden and estimate 10-year survival using the validated CCI scoring system from Charlson et al. 1987.
CCRC Calculator
Free Continuing Care Retirement Community (CCRC) cost calculator. Compare CCRC contract types, entrance fees, and lifetime costs against aging in place and assisted living alternatives.
Child BMI Percentile Calculator
Free Child Body Mass Index (BMI) Percentile Calculator using CDC LMS method — computes age- and sex-adjusted BMI percentile, Z-score, weight category, and percent of 95th percentile for children ages 2–20.
Child Height Predictor
Free child height predictor using Mid-Parental Height, Khamis-Roche, and Multiplier methods. Predict your child's adult height with confidence ranges and percentile rankings.
Circle Skirt Calculator
Free Circle Skirt Calculator — instantly compute waist radius, hem radius, and fabric yardage for full, three-quarter, half, and quarter circle skirts with seam allowances.
CLV Calculator
Free Customer Lifetime Value (CLV) calculator — compute LTV using SaaS/subscription, simple eCommerce, or DCF-traditional formulas. Includes LTV:CAC ratio, CAC payback period, cohort projection chart, and churn sensitivity analysis.
CNC Feed Rate Calculator
Free CNC Feed Rate and Speeds Calculator — compute feed rate, spindle RPM, surface speed, plunge rate, stepover, pass depth, and material removal rate for milling, drilling, and turning operations. Supports Imperial and Metric units with material presets.
CNC Spindle Speed Calculator
Free CNC Spindle Speed (RPM) calculator — find the correct spindle speed for any tool diameter, cutting speed, and material. Includes feed rate companion output, HSS vs carbide comparison, material SFM reference table, and three calculation modes: Find RPM, Find Surface Speed, and Find Feed Rate.
Coffee Calculator
Free coffee-to-water ratio calculator for every brew method. Get perfect coffee measurements in grams and tablespoons for Pour Over, French Press, Espresso, AeroPress, Cold Brew, and 11+ methods.
College GPA Calculator
Free College GPA Calculator — compute your semester GPA, cumulative GPA with prior history, plan the grades you need to hit a target GPA, and download a CSV of your full course record.
Color Codes Chart
Free Color Codes Chart and Converter — instantly convert HEX, RGB, HSL, HSV, and CMYK color codes with live preview, shade/tint generation, WCAG contrast checking, and a full 140-color HTML/CSS named color reference chart.
Compound Interest Calculator
Free compound interest calculator to see how your savings and investments grow over time with the power of compounding.
Conception Date Calculator
Free conception date calculator using LMP, due date, ultrasound, birth date, or IVF transfer method. Calculate your conception date, fertile window, implantation window, trimester dates, and clinical milestones.
Concrete Slab Calculator
Free Concrete Slab Calculator — estimate cubic yards, cubic feet, and cubic meters for slabs, walls, and round columns. Get bag counts for 40 lb, 60 lb, and 80 lb premix bags plus cost estimates.
Connections Game
Free Connections word puzzle game — group 16 words into 4 hidden categories before making 4 mistakes. Play unlimited puzzles inspired by NYT Connections.
Cooking Conversion Calculator
Free Cooking Conversion Calculator — convert volume, weight, and temperature units for recipes. Supports 15+ volume units (US and UK), 5 weight units, temperature in Celsius, Fahrenheit, and Kelvin, Gas Mark reference, and 20 ingredient-specific density conversions.
Cost Per Hire Calculator
Free cost per hire calculator — calculate your total recruiting cost per hire, split internal and external costs, benchmark against SHRM data, and project annual hiring budgets.
CPC Calculator
Free Cost Per Click (CPC) Calculator — calculate CPC, campaign ROI, ROAS, CPA, and CPM/CTR metrics. Compare your CPC against platform and industry benchmarks.
CPM Calculator
Free Cost Per Mille (CPM) calculator — solve for CPM, total ad spend, or impressions instantly. Includes platform benchmarks, CPC/CTR metrics, budget planner, and ROI tracking for Google, Facebook, LinkedIn, TikTok, and more.
CRC Calculator
Free corrected reticulocyte count (CRC) calculator. Calculate CRC, RPI, and absolute reticulocyte count with clinical interpretation for anemia assessment.
Critical Path Calculator
Free Critical Path Method (CPM) calculator with Gantt chart — compute ES, EF, LS, LF, Total Float, Free Float, and the critical path for any project network.
Crochet Gauge Calculator
Free crochet gauge calculator — measure your swatch, find stitches and rows per inch or cm, classify yarn weight, plan project stitch counts, and adjust gauge to match any pattern.
Crochet Hook Size Converter
Free Crochet Hook Size Converter — instantly translate between Metric (mm), US letter-number, and UK/Canadian old-number systems. Includes yarn weight recommendations, steel hook chart, and full printable reference table.
Crop Water Requirement Calculator
Free Crop Water Requirement (ETc) calculator using FAO-56 crop coefficients. Calculate daily and seasonal irrigation needs, effective rainfall, gross irrigation requirements, and irrigation scheduling for 35+ crops across all growth stages.
Crop Yield Calculator
Free Crop Yield Calculator — estimate grain and vegetable yields in bushels per acre, tonnes per hectare, or total weight. Supports corn, wheat, soybeans, tomatoes, and more.
Cubic Equation Solver
Free Cubic Equation Solver — instantly find all three roots (real and complex) of any ax³ + bx² + cx + d = 0 equation with step-by-step solution, discriminant analysis, factored form, Vieta's verification, and a polynomial graph.
Cubic Yard Calculator
Free Cubic Yard Calculator — calculate volume in cubic yards, cubic feet, and cubic meters for landscaping, construction, and material delivery. Supports rectangular, circular, triangular, and trapezoidal shapes with weight estimates.
Cumulative GPA Calculator
Free Cumulative Grade Point Average (GPA) calculator — track your GPA across multiple semesters, include prior credit history, plan toward a target GPA, and visualize your grade distribution instantly.
Cups to Grams Converter
Free Cups to Grams Converter — accurately convert between cups and grams for 30+ common cooking ingredients. Includes density database for flours, sugars, liquids, fats, and grains with bidirectional conversion.
Currency Exchange Calculator
Free Currency Exchange Calculator — compare bank fees, Wise, and airport kiosk rates for 30 currencies. See exactly how much you receive after all fees.
Cycle Time Calculator
Free Cycle Time Calculator — calculate manufacturing cycle time, takt time, production rate, and process efficiency. Supports basic, net production time, and quality-adjusted formulas.
Date Difference Calculator
Free Date Difference Calculator — instantly find the exact number of days, weeks, months, and years between any two dates. Includes business days mode, time breakdown, and milestone detection.
Decking Calculator
Free Decking Calculator — estimate board count, linear footage, joist count, fasteners, and total material cost for your deck project. Supports pressure-treated lumber, composite, cedar, PVC, and hardwood with Imperial and metric units.
Delta-V Calculator
Free Delta-V (Δv) rocket equation calculator using the Tsiolkovsky equation. Solve for velocity change, initial mass, final mass, or Isp with multi-stage support, engine presets, and mission budgets.
Dilution Calculator
Free Dilution Calculator using the C1V1=C2V2 formula. Solve for any variable — stock concentration, stock volume, final concentration, or final volume — with multi-unit support, ratio mode, and serial dilution steps.
Dimensional Weight Calculator
Free Dimensional Weight (DIM weight) calculator — compare billable weight across FedEx, UPS, USPS, DHL, and Canada Post using 2024 verified DIM factors. Supports multi-piece shipments, custom DIM factors, and packaging efficiency analysis.
Discount Calculator
Free discount calculator to quickly calculate sale prices, savings, stacked discounts, and final costs including sales tax.
Dog Age Calculator
Convert your dog's age to human years using modern veterinary science. Size-based formulas for Small, Medium, Large, and Giant breeds with life stage identification and health tips.
Dosage Calculator
Free dosage calculator for weight-based dosing, nursing D/H/Q method, pediatric rules (Clark's, Young's, Fried's, BSA), and IV drip rate. Supports mg, mcg, g units with liquid volume and tablet count outputs.
DPS Calculator
Free Damage Per Second (DPS) Calculator for any game — compute burst DPS, sustained DPS, effective DPS after armor, critical hit contributions, elemental damage, time to kill, and more.
DRI Calculator
Free Dietary Reference Intakes (DRI) calculator. Get personalized RDA, AI, UL, and EAR values for all vitamins, minerals, and macronutrients based on your age, sex, and life stage.
Drill Speed Calculator
Free Drill Speed and Feed Calculator — compute RPM, feed rate (IPM), chip load (IPT), cut time, and thrust force for any drill bit, material, and unit system.
DSCR Calculator
Free Debt Service Coverage Ratio (DSCR) calculator for real estate investors and lenders. Instantly compute your DSCR, NOI, and debt service from rental income, loan parameters, and PITIA expenses — with fixed vs. interest-only comparison.
EER Calculator
Free Estimated Energy Requirement (EER) calculator using official IOM/DRI equations. Calculate daily calorie needs for all life stages — infants, children, adolescents, adults, pregnancy, and lactation.
Electricity Bill Calculator
Free electricity bill calculator — estimate your monthly electricity costs by appliance, calculate bills from meter readings, compare electricity rates, and track annual CO2 emissions.
Equation Solver
Free Equation Solver — solve linear, quadratic, and systems of equations step-by-step with discriminant analysis, factored forms, and verification checks.
Ethereum Mining Calculator
Free Ethereum Staking Calculator — estimate your ETH staking rewards based on amount staked, current APR, validator fees, and compounding. Project earnings over time with detailed year-by-year breakdowns.
EV Calculator
Free Exposure Value (EV) calculator for photographers. Calculate EV from aperture, shutter speed, and ISO. Find equivalent exposures, apply ND filters, and map EV to real-world lighting conditions.
Fabric Yardage Calculator
Free Fabric Yardage Calculator — instantly calculate how much fabric you need for any sewing, quilting, or craft project. Supports seam allowance, pattern repeat, shrinkage, directional prints, dual-orientation comparison, and shows results for both 45" and 60" fabric widths.
Fence Calculator
Free fence calculator that estimates posts, pickets, rails, nails, and material costs for wood, vinyl, chain-link, aluminum, cedar, redwood, and composite fences.
Fertilizer Calculator
Free NPK Fertilizer Calculator — determine exactly how much fertilizer you need, what nutrients you are applying, and how to blend multiple fertilizer products for optimal plant nutrition.
FFMI Calculator
Free Fat-Free Mass Index (FFMI) calculator. Calculate your FFMI, adjusted FFMI, and see how your muscle mass compares to natural and competitive bodybuilding standards.
Field of View Calculator
Free Camera Field of View (FOV) Calculator — compute horizontal, vertical, and diagonal angles of view plus linear scene coverage at any distance for any lens and sensor combination.
Framing Calculator
Free wall framing calculator for stud-framed walls. Calculate stud count, plate lengths, sheathing sheets, header sizes (IRC R602.7), and total material cost for any wall section.
Freight Class Calculator
Free National Motor Freight Classification (NMFC) Freight Class Calculator — instantly determine your LTL freight class, density (lbs/ft³), volume, and estimated shipping cost for any shipment.
Fuel Economy Calculator
Free fuel economy calculator — calculate MPG, L/100km, trip fuel costs, annual fuel expenses, and compare two vehicles side by side. Supports imperial and metric units.
GCF Calculator
Free Greatest Common Factor (GCF) calculator — also known as GCD or HCF. Find the GCF of 2 to 10 numbers instantly with step-by-step solutions using Euclidean algorithm, prime factorization, or listing factors.
GCS Calculator
Free Glasgow Coma Scale (GCS) calculator with Adult and Pediatric modes, GCS-P pupil scoring, NT (Not Testable) support, standard clinical notation, and visual score breakdown.
GFR Calculator
Free eGFR calculator using CKD-EPI 2021, MDRD, and Cockcroft-Gault formulas. Calculate your estimated glomerular filtration rate and CKD stage with side-by-side formula comparison.
GIR Calculator
Free GIR Calculator for computing Glucose Infusion Rate (mg/kg/min) from dextrose concentration, infusion rate, and patient weight. Supports multiple infusion lines, reverse calculation, and clinical target ranges.
Glycemic Index Calculator
Free glycemic index and glycemic load calculator with a database of 100+ foods. Lookup GI values, calculate GL per serving, and track your meal's total glycemic load.
GPA Calculator
Calculate gpa quickly and accurately
GPU Mining Calculator
Free GPU Mining Profitability Calculator — estimate daily, weekly, monthly, and yearly crypto mining profits for your graphics card. Includes electricity break-even rate, ROI timeline, and power sensitivity analysis.
Grams to Milligrams Converter
Free Grams to Milligrams (g to mg) converter — instantly convert between grams and milligrams with bidirectional conversion, multi-unit output, quick presets for common medical doses, and a visual reference chart.
Grams to Moles Calculator
Free grams to moles calculator — convert any mass in grams to moles (and moles to grams) using molar mass. Supports chemical formula parsing, elemental composition charts, and Avogadro's number output.
Gross to Net Pay Calculator
Free Gross to Net Pay Calculator — instantly convert your gross salary or hourly wage into take-home pay. Calculates federal and state income taxes, FICA (Social Security and Medicare), pre-tax deductions, and more for all 50 U.S. states.
Growth Chart Calculator
Free pediatric growth chart calculator using WHO 2006 and CDC 2000 LMS data tables. Plot weight, height, head circumference, and BMI percentiles for children ages 0–20 years. Includes mid-parental height predictor, preterm age correction, and Z-score outputs.
Habitable Zone Calculator
Free Habitable Zone (HZ) Calculator using Kopparapu et al. (2013/2014) polynomial model — compute conservative and optimistic HZ boundaries, equilibrium temperature, stellar lifetime, snow line, ESI score, and more for any star.
hCG Calculator
Free hCG doubling time calculator and beta hCG level lookup. Calculate pregnancy hormone doubling time, percentage change, 48-hour projection, and compare your hCG level to normal ranges by gestational week.
Heart Rate Calculator
Free heart rate calculator to find your maximum heart rate, target heart rate zones, and heart rate reserve using multiple scientifically-validated formulas.
Hohmann Transfer Calculator
Free Hohmann Transfer Orbit Calculator — compute delta-V burns, transfer time, orbital velocities, and propellant mass for transfers between two circular orbits or between planets.
Hourly to Salary Calculator
Free Hourly to Annual Salary Calculator — enter your hourly wage (or any pay period) and instantly see your full earnings breakdown: annual, monthly, bi-weekly, weekly, and daily. Includes holiday and vacation adjustments, overtime preview, and visual charts.
HSI Calculator
Free online HSI Calculator to assess your nicotine dependence level using the validated 2-question Heaviness of Smoking Index. Get personalized cessation recommendations.
Hubble Constant Calculator
Free Hubble Constant (H₀) Calculator — solve Hubble's Law bidirectionally for recession velocity, distance, redshift, and universe age with spectral line presets.
ICH Calculator
Free Intracerebral Hemorrhage (ICH) Score calculator. Predict 30-day mortality risk using the validated Hemphill ICH grading scale with built-in GCS and ABC/2 volume helpers.
Ideal Weight Calculator
Free ideal weight calculator using Devine, Robinson, Miller, Hamwi, Peterson, and Lorentz formulas. Find your ideal body weight based on height, gender, and frame size with BMI-based healthy weight ranges.
Imposter Game
Free online Imposter Game — a pass-and-play social deduction word game for 3-8 players. One player gets a different word and must blend in while the crew tries to identify the imposter through discussion and voting.
Infant Fever Dosage Calculator
Free Infant Fever Dosage Calculator — calculate accurate weight-based acetaminophen (Tylenol) and ibuprofen (Motrin/Advil) doses for babies and children. Includes safety alerts, formulation selector, fever severity assessment, and AAP-based guidelines.
INR Calculator
Free INR calculator. Convert prothrombin time (PT) to INR using the standard formula. Includes interpretation, warfarin dose guidance, therapeutic range comparison, and INR trend tracker.
Irrigation Water Calculator
Free Irrigation Water Calculator — calculate irrigation run time, water volume per event, irrigation interval, precipitation rate, and soil water balance using FAO-56 methods. Supports drip, sprinkler, pivot, and flood systems with metric and imperial units.
ISS Calculator
Free Injury Severity Score (ISS) calculator. Calculate ISS, NISS, and TRISS probability of survival from AIS body region scores for trauma assessment.
Jigsaw Puzzle Game
Free online jigsaw puzzle game — play instantly in your browser with colorful pattern puzzles. Choose from Beginner (9 pieces) to Expert (100 pieces), drag and drop pieces on desktop or mobile, enable rotation mode for extra challenge, and track your best times.
JSON Formatter
Free online JSON Formatter, Validator, and Beautifier. Instantly format, minify, validate, and repair JSON data in your browser — 100% client-side, nothing is sent to a server.
Kakuro Game
Free online Kakuro number crossword puzzle game with pencil marks, undo/redo, combination helper, hints, and 6 built-in puzzles across easy, medium, and hard difficulty levels.
KenKen Game
Free KenKen (Calcudoku / MathDoku) math puzzle game. Fill the NxN grid with digits, satisfy cage arithmetic targets, and never repeat a number in any row or column.
Kg to Tons Converter
Free Kilograms to Tons converter — instantly convert kg to metric tons (tonnes), US short tons, or UK long tons with formula display, all-unit equivalents, and reference table.
km/h to mph Converter
Free kilometers per hour to miles per hour converter. Instantly convert km/h to mph and mph to km/h with a reference table, bulk conversion, and speed context labels.
Knitting Gauge Calculator
Free Knitting Gauge Calculator — find your stitches and rows per inch or cm, plan your project cast-on count, adjust any pattern to your personal gauge, and reverse-calculate finished dimensions from stitch counts.
Knitting Stitch Calculator
Free Knitting Stitch Calculator — calculate cast-on stitches from gauge, distribute increases and decreases evenly, align stitch multiples, plan sleeve shaping, and estimate yarn yardage for any project.
Korean Age Calculator
Free Korean age calculator. Find your Korean age (세는 나이), international age (만나이), and year age (연나이) instantly. Includes zodiac animals, countdown timers, and 2023 legal reform context.
LCM Calculator
Free Least Common Multiple (LCM) Calculator — find the LCM of 2 to 10 integers instantly with step-by-step solutions using prime factorization, GCF method, or listing multiples.
LDL Cholesterol Calculator
Free LDL cholesterol calculator using Friedewald, Martin-Hopkins, and Sampson equations. Calculate LDL-C from total cholesterol, HDL, and triglycerides with risk classification.
Lease Calculator
Free lease calculator for cars and assets. Compute monthly payments, total lease cost, due at signing, money factor to APR conversion, cost per mile, and full payment breakdown.
Letter Grade Calculator
Free Letter Grade Calculator — convert percentage scores or points into letter grades (A+ through F), GPA equivalents, and weighted averages. Includes EZ Grader mode and Final Exam Planner.
Life Expectancy Calculator
Free life expectancy calculator using CDC actuarial data and 10 lifestyle factors. Get your estimated lifespan, biological age, healthy years, and personalized risk factor breakdown.
Life Insurance Needs Calculator
Free Life Insurance Needs Calculator — estimate how much life insurance coverage your family needs based on income, debts, mortgage, education expenses, and existing assets.
Light Year to Parsec Converter
Free Light Year to Parsec Converter — instantly convert between light-years (ly), parsecs (pc), kiloparsecs (kpc), megaparsecs (Mpc), gigaparsecs (Gpc), astronomical units (AU), kilometers, and miles. Includes all-unit breakdown, cosmic scale indicator, famous distances reference, light travel time, parallax converter, and preset famous astronomical objects.
Linear Equation Solver
Free Linear Equation Solver — solve single-variable equations (ax + b = c), slope-intercept form (y = mx + b), two-point form, and standard form (Ax + By = C) with step-by-step solutions, line graphs, and form conversions.
Little Alchemy Game
Free Little Alchemy browser game — combine Water, Fire, Earth, and Air to discover 150 elements. No download needed, pure drag-and-drop element crafting with emoji icons.
Loan Calculator
Calculate monthly loan payments, total interest, and payment breakdown for mortgages, auto loans, and personal loans
Log Calculator
Free Logarithm (Log) Calculator — compute log base 10, natural log (ln), binary log (log2), antilog, change of base, and solve for any logarithm variable with step-by-step solutions and real-world examples.
Logarithm Calculator
Free Logarithm Calculator — compute log, antilog, natural log, binary log, and custom-base logarithms. Solve log equations, generate log tables, and explore scientific applications like pH, decibels, Richter scale, and doubling time.
Lunar Eclipse Calculator
Free Lunar Eclipse Calculator — browse upcoming total, partial, and penumbral lunar eclipses from 2026 to 2032 with contact times, magnitude, visibility regions, and local time conversion.
Macro Calculator
Free macronutrient calculator to determine your ideal daily intake of protein, carbs, and fat. Uses Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas with 6+ diet presets.
Match-3 Game
Free online Match-3 gem puzzle game — swap adjacent colored gems to create chains of 3 or more, trigger special tiles, and cascade for combo bonuses. Play Classic, Timed, or Moves mode.
Matrix Calculator
Free online Matrix Calculator for addition, subtraction, multiplication, determinant, inverse, transpose, eigenvalues, RREF, LU decomposition, and linear system solving — all computed instantly in your browser.
Matrix Determinant Calculator
Free Matrix Determinant Calculator — compute the determinant of 2x2, 3x3, 4x4, 5x5, and 6x6 matrices with step-by-step solutions using the Sarrus rule and cofactor expansion.
Matrix Inverse Calculator
Free matrix inverse calculator with step-by-step Gauss-Jordan elimination and adjugate method. Supports 2×2, 3×3, 4×4, and 5×5 matrices with fraction and decimal output.
Max Heart Rate Calculator
Free max heart rate calculator with training zones, Karvonen method, and multi-formula comparison. Calculate your target heart rate zones for fat loss, endurance, and performance.
MCA-PSV Calculator
Free MCA-PSV calculator for fetal anemia assessment. Calculate MoM value from gestational age and MCA Doppler measurement using the Mari et al. formula.
Mg to Grams Converter
Free Milligrams to Grams Converter — instantly convert between mg and grams with bidirectional conversion, pharmaceutical presets, and a complete multi-unit reference including micrograms, kilograms, ounces, pounds, and grains.
Military COLA Calculator
Free Military Cost of Living Allowance (COLA) calculator for CONUS and OCONUS duty stations. Estimate your monthly and annual COLA entitlement for 2026 based on pay grade, years of service, dependency status, and duty station location.
Military Pay Calculator
Free US Military Pay Calculator — compute 2026 Basic Pay, BAH, BAS, special pays, total compensation, retirement pay, and civilian salary equivalent for all pay grades E-1 through O-10.
Military Retirement Pay Calculator
Free Military Retirement Pay Calculator — estimate your U.S. military pension under Legacy/Final Pay, High-36, REDUX/CSB, or BRS using 2026 DFAS pay tables, COLA projections, SBP costs, and TSP growth estimates.
Minesweeper Game
Play the classic Minesweeper puzzle game free online — no download required. Three difficulty levels (Beginner 9x9, Intermediate 16x16, Expert 30x16), custom grid, flag counter, timer, and personal best times.
Mini Crossword Game
Free online mini crossword puzzle game — solve 5x5 themed crosswords with across and down clues, timer, check, reveal, and pencil mode.
mL to Grams Calculator
Free milliliters to grams (mL to g) calculator with 50+ ingredient presets. Convert any volume to weight using ingredient-specific density. Supports bidirectional conversion, multi-unit input/output, and recipe scaling.
mL to oz Converter
Free Milliliters to Fluid Ounces (mL to oz) converter. Instantly convert mL to US or UK fluid ounces, oz to mL, with ingredient-based weight conversion, kitchen context labels, and a full reference table.
ML to Tablespoons Converter
Free milliliters to tablespoons converter supporting US, Metric, UK, and Australian tablespoon standards. Convert ml to tbsp instantly with bidirectional conversion, fraction display, batch mode, and a full cooking reference table.
ML to Teaspoons Converter
Free milliliters to teaspoons converter supporting US Customary (4.929 mL), Metric (5 mL), and Imperial/UK (5.919 mL) standards. Bidirectional conversion with fraction display, preset values, reference table, and CSV export.
MME Calculator
Free MME calculator using CDC 2022 conversion factors. Calculate total daily morphine milligram equivalents for single or multiple opioids, assess overdose risk level, and convert between opioids.
Moles to Grams Calculator
Free Moles to Grams Calculator — convert moles to grams or grams to moles using molar mass. Supports chemical formula parsing, multi-unit inputs, Avogadro's number, and elemental breakdown.
Moon Phase Calculator
Free Moon Phase Calculator — instantly find the current lunar phase for any date, including illumination percentage, moon age, upcoming phases, gardening guidance, and more.
Mortgage Calculator
Free mortgage calculator to estimate monthly payments, total interest, and view a full amortization schedule.
MPG Calculator
Free MPG Calculator — calculate your vehicle's fuel economy in miles per gallon, km/L, and L/100km. Estimate annual fuel costs, cost per mile, and CO₂ emissions with US, Imperial, and Metric unit support.
MPH to KMH Converter
Free Miles Per Hour (MPH) to Kilometers Per Hour (KMH) converter with bidirectional conversion, multi-unit output, speed context labels, and a visual speed comparison chart.
Needle Size Converter
Free knitting needle and crochet hook size converter — convert instantly between Metric (mm), US, UK, and Japanese sizing systems with yarn weight recommendations.
Needle Size Converter
Free knitting needle and crochet hook size converter — convert instantly between Metric (mm), US, UK, and Japanese sizing systems with yarn weight recommendations.
NeoPixel Power Calculator
Free NeoPixel and addressable LED strip power calculator. Estimate total current draw, wattage, PSU size, wire gauge, voltage drop, and power injection points for WS2812B, SK6812, APA102, and more.
Net Promoter Score Calculator
Free Net Promoter Score (NPS) calculator — enter your survey responses by score or aggregate totals, get your NPS instantly with segment breakdown, industry benchmark comparison, and actionable improvement tips.
Nitrogen Application Calculator
Free Nitrogen Application Calculator — determine the precise amount of nitrogen fertilizer needed for your crops by accounting for yield goals, soil nitrate levels, legume rotation credits, manure and cover crop credits, fertilizer form, and application efficiency. Supports corn, wheat, barley, sorghum, potato, and more.
NLR Calculator
Free NLR calculator. Compute your Neutrophil-to-Lymphocyte Ratio from CBC values, get risk classification, disease context, and related immune-inflammation indices (PLR, SII, LMR).
NNT Calculator
Free Number Needed to Treat (NNT) calculator. Compute NNT, NNH, ARR, RRR, relative risk, and odds ratio from clinical trial data with confidence intervals, sensitivity analysis, and visual charts.
Nonogram Game
Free Nonogram (Picross / Griddlers / Hanjie) puzzle game — solve picture logic puzzles online. Over 15 pre-built puzzles across 5x5 to 15x15 grids, with undo, hints, error checking, and mobile touch support.
NPK Calculator
Free NPK Calculator — analyze fertilizer blend ratios, decode label nutrition content, and optimize mixing proportions to hit a target N-P-K rate for your crop or lawn.
OEE Calculator
Free Overall Equipment Effectiveness (OEE) calculator — measure Availability, Performance, and Quality to find your hidden factory and eliminate the Six Big Losses.
One Rep Max Calculator
Free one rep max calculator with all 7 formulas (Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, Wathen). Get your 1RM estimate, training load table, warm-up sets, plate loading, and strength standards.
Orbital Period Calculator
Free Planet Orbital Period Calculator using Kepler's Third Law — compute orbital period, semi-major axis, or central body mass for any planet, moon, or exoplanet orbiting any star.
Overtime Calculator
Free Overtime Pay Calculator — instantly compute your overtime hourly rate, regular pay, overtime pay, total earnings per period, and annual projections. Supports 1.5x, 2.0x, 2.5x, 3.0x or custom multipliers, tiered California-style double-time, multiple currencies, and pay period scaling.
Pace Calculator
Free running pace calculator with three solve modes: calculate pace, time, or distance. Includes race presets, split tables with even/negative/positive strategy, Riegel race predictor, pace zones, training zones, pace bands, and calorie estimator.
Parallax Distance Calculator
Free Stellar Parallax Distance Calculator — convert parallax angles to distances in parsecs, light-years, AU, and km. Includes preset famous stars, bidirectional mode, distance modulus, and precision tier analysis.
Payment Calculator
Free loan payment calculator — calculate monthly, biweekly, or weekly payments for mortgages, auto loans, personal loans, and student loans with a full amortization schedule.
PCB Trace Width Calculator
Free PCB Trace Width Calculator based on IPC-2221 and IPC-2152 standards. Calculate the minimum copper trace width required to safely carry a given current with your chosen temperature rise, copper weight, and layer type.
PCB Via Size Calculator
Free PCB via size calculator using IPC-2221 and IPC-2152 standards. Calculate via current capacity, resistance, voltage drop, power loss, aspect ratio, annular ring, inductance, and capacitance for through-hole, blind, buried, and microvias.
Percentage Calculator
Calculate percentages, percentage increase/decrease, and find what percentage one number is of another
Percentage Off Calculator
Free Percentage Off Calculator — instantly calculate the sale price, amount saved, and total discount for any original price and percent-off value. Supports stacked discounts, sales tax, reverse calculations, and a full discount comparison table.
Periodic Table
Free interactive Periodic Table of the Elements — explore all 118 elements with detailed properties, color-coded categories, search, filters, temperature-based state visualization, and a molar mass builder.
Planting Density Calculator
Free Planting Density Calculator — calculate plants per acre, hectare, or square foot from row and in-row spacing. Supports square, triangular, hexagonal, and diamond patterns with 14 crop presets and seed requirement estimates.
Population Growth Calculator
Free population growth calculator — model exponential, continuous, logistic, and linear population growth. Calculate final population, doubling time, and view growth timelines with four mathematical models.
Potential Energy Calculator
Free Potential Energy (PE) calculator for gravitational, elastic, and electric potential energy. Solve for any variable with step-by-step solutions, planet gravity presets, and multi-unit output.
Pregnancy Due Date Calculator
Free pregnancy due date calculator using 4 methods: Last Menstrual Period (LMP), Conception Date, Ultrasound, and IVF Transfer Date. See your estimated due date, gestational age, trimester progress, baby size comparison, milestones timeline, and more.
Profit Calculator
Free Profit and Profit Margin Calculator — instantly calculate net profit, profit margin %, and markup % from cost and revenue. Supports simple, markup-based, and advanced cost-breakdown modes.
Protein Intake Calculator
Free protein intake calculator. Get your personalized daily protein recommendation based on your weight, activity level, fitness goal, and body composition. Includes per-meal breakdown, caloric context, protein tiers, and food sources.
PSI Calculator
Free Pneumonia Severity Index (PSI/PORT Score) calculator. Calculate your PSI risk class, 30-day mortality rate, and get evidence-based disposition recommendations for community-acquired pneumonia.
Punnett Square Calculator
Free Punnett Square Calculator for monohybrid, dihybrid, and trihybrid crosses. Visualize genotype and phenotype ratios, probability percentages, zygosity labels, and Mendelian ratios instantly.
PVR Calculator
Free online PVR calculator for pulmonary vascular resistance. Calculate PVR in Wood units and dynes·sec/cm⁵, PVRI, transpulmonary gradient, and clinical severity with reference ranges.
QTc Calculator
Free QTc calculator using all 5 correction formulas: Bazett, Fridericia, Framingham, Hodges, and Rautaharju. Includes gender-specific thresholds, drug-induced QT prolongation risk information, and clinical interpretation.
RC Time Constant Calculator
Free RC (Resistor-Capacitor) Time Constant (τ) calculator — compute τ = R × C, cutoff frequency, rise time, energy stored, and charging/discharging curves. Supports RC and RL circuits with solve-for-any mode.
Redshift Calculator
Free cosmological Redshift Calculator — compute recession velocity, luminosity distance, lookback time, and more from spectral wavelengths or redshift z using the ΛCDM model with Planck 2018 parameters.
Reenlistment Bonus Calculator
Free Selective Reenlistment Bonus (SRB) calculator for U.S. military members — estimate your gross bonus, net take-home after taxes, lump sum payment, and annual installment schedule across all six branches.
Resistor Color Code Chart
Free Resistor Color Code Chart and Calculator — decode 3-band, 4-band, 5-band, and 6-band resistors instantly. Includes reverse lookup, parallel/series calculator, SMD decoder, and full IEC 60062 reference table.
RMR Calculator
Free RMR calculator using Mifflin-St Jeor, Cunningham, and Harris-Benedict formulas. Calculate your resting metabolic rate, TDEE, and daily calorie needs.
ROAS Calculator
Free Return on Ad Spend (ROAS) calculator with three modes: simple ROAS, campaign planner, and goal solver. Calculate your ROAS ratio, percentage, break-even ROAS, and compare against industry benchmarks.
Rock Climbing Grade Converter
Free Rock Climbing Grade Converter — instantly convert between YDS, French, UIAA, British, Australian, South African, Hueco V-Scale, and Fontainebleau bouldering grades with difficulty band labels and a full reference table.
Roof Pitch Calculator
Free Roof Pitch Calculator — instantly convert between pitch ratio (X:12), angle in degrees, slope percentage, and rafter length. Includes framing cut angles, material recommendations, roof area estimator, and a visual roof diagram.
Salary Benchmarking Calculator
Free Salary Benchmarking Calculator — compare your compensation against market percentiles (P10–P90), calculate your compa-ratio, generate a pay band, and see total compensation estimates for 50+ roles across all industries and US locations.
Salary to Hourly Calculator
Free Salary to Hourly Rate Calculator — instantly convert any pay period (hourly, daily, weekly, bi-weekly, monthly, or annual) to a full earnings breakdown. Includes holiday and vacation adjustments, overtime preview, and visual charts.
Sales Tax Calculator
Free sales tax calculator to add tax to a price, extract tax from a total, and calculate sales tax for multiple items. Includes quick-select US state tax rates.
Sand Calculator
Free Sand Calculator — estimate how much sand, gravel, or topsoil you need for any project. Enter your area dimensions, choose a material type, and instantly get volume in cubic yards and feet, weight in tons and pounds, bag counts, and optional cost estimates.
Schwarzschild Radius Calculator
Free Schwarzschild Radius (event horizon) calculator — compute the critical radius at which any mass becomes a black hole, surface gravity, average density, Hawking temperature, photon sphere, and ISCO radius.
Seed Rate Calculator
Free Seed Rate Calculator — determine the optimal seeding rate in lbs/acre, kg/ha, and seeds/acre for corn, wheat, soybeans, canola, and 14 other crops. Accounts for germination, field emergence losses, seed purity, and seeding method.
Seeding Rate Calculator
Free Seeding Rate Calculator — determine the optimal pounds per acre (lbs/acre) or kilograms per hectare (kg/ha) of seed to plant for any crop. Supports 14 crops with presets, TKW/seeds-per-lb toggle, germination and emergence loss inputs, total seed cost, and stacked-bar seed fate chart.
Sleep Calculator
Free sleep calculator to find the best bedtime or wake-up time based on sleep cycles. Get personalized recommendations for optimal rest using scientifically-backed 90-minute sleep cycle intervals.
Sleeping Bag Temperature Calculator
Free Sleeping Bag Temperature Rating Calculator — find the exact EN/ISO comfort and lower limit rating you need based on overnight lows, shelter type, wind, humidity, altitude, clothing layers, and liner warmth. Includes sleep system comparator and pad R-value adequacy check.
Sliding Puzzle Game
Free online Sliding Puzzle game — play the classic 8-Puzzle (3x3), 15-Puzzle (4x4), or 24-Puzzle (5x5). Drag tiles into order with arrow keys, click, or touch swipe. Personal best tracking included.
Smoking Cost Calculator
Calculate the true financial cost of smoking. See daily, weekly, monthly, and yearly costs, future projections with inflation, investment opportunity cost, and health benefits of quitting.
Soil Calculator
Free Soil Calculator — quickly estimate how much topsoil, garden soil, or potting mix you need for any lawn, garden bed, raised bed, or container project. Calculate cubic yards, cubic feet, bags needed, and weight.
Soil pH Calculator
Free Soil pH Calculator — determine exactly how much agricultural lime or elemental sulfur you need to raise or lower your soil pH to the ideal level for your crop. Enter your current pH, target pH, soil texture, and field area for instant, research-backed amendment recommendations.
Sokoban Game
Free classic Sokoban puzzle game — push boxes onto goal squares across 20 progressively challenging levels. No login required, works on mobile and desktop.
Solar Eclipse Calculator
Free Solar Eclipse Calculator — browse upcoming solar eclipses from 2025 to 2030, explore eclipse types (total, annular, partial, hybrid), view magnitude and obscuration data, contact times, Saros series, and countdown to the next solar eclipse event.
Solar Panel Calculator
Free Solar Panel Calculator — estimate the number of panels, system size, battery storage, and 25-year payback for residential and off-grid solar installations.
Soul Urge Number Calculator
Free Soul Urge Number (Heart's Desire Number) calculator — enter your full birth name to reveal your innermost desires, motivations, and spiritual drives through Pythagorean numerology.
Speaker Crossover Calculator
Free Speaker Crossover Calculator — design passive crossover networks for 2-way and 3-way speaker systems. Calculates capacitor (µF) and inductor (mH) values for Butterworth, Linkwitz-Riley, Bessel, and Chebyshev filters with Zobel and L-pad support.
Spiral Staircase Calculator
Free Spiral Staircase Calculator — design code-compliant spiral stairs with riser height, tread depth, handrail length, stringer lengths, Blondel comfort score, and IBC/IRC compliance checks.
Split Bill Calculator
Free Split Bill Calculator — divide restaurant checks, group meals, and shared expenses equally or by item, with tip, tax, and service fee splitting built in.
Sprint Velocity Calculator
Free Sprint Velocity Calculator for Agile teams — track story points per sprint, forecast release dates, and measure team consistency with optimistic, expected, and pessimistic scenario analysis.
Square Yards Calculator
Free Square Yards Calculator — instantly calculate area in square yards for any shape. Supports rectangles, squares, circles, triangles, trapezoids, parallelograms, and ellipses with per-field unit selection, waste/overage percentage, cost estimation, multi-room mode, and CSV export.
Steel Plate Weight Calculator
Free steel plate weight calculator — calculate the weight of rectangular, square, circular, ring, and perforated metal plates in kg, lb, and metric tons for any material density.
Steel Weight Calculator
Free Steel Weight Calculator — instantly calculate the weight of any steel shape (round bar, square bar, plate, pipe, I-beam, angle, channel) in kg, lbs, and metric tonnes. Supports 12+ materials, batch bill-of-materials mode, cost estimation, CSV export, and standard profile lookup (IPE, HEA, HEB, W-shapes).
Steps to Miles Calculator
Free steps to miles calculator. Convert steps to miles and kilometers instantly with calorie burn, walking time, stride length, and 10,000-step goal progress.
Stone Calculator
Free Stone & Gravel Calculator — estimate volume (cu ft, cu yd, cu m), weight (lbs, tons, kg, tonnes), bag count, truck loads, and total cost for any landscaping or construction project.
Sudoku Game
Free online Sudoku puzzle game with Easy, Medium, Hard, and Expert difficulty levels. Features notes mode, undo, hints, auto-save, and keyboard navigation.
Sunrise Sunset Calculator
Free Sunrise and Sunset Calculator — find exact sunrise, sunset, solar noon, twilight, golden hour, and blue hour times for any location and date using the Jean Meeus / NOAA solar algorithm.
Takt Time Calculator
Free Takt Time calculator for lean manufacturing — compute the maximum allowed production time per unit from net available time and customer demand, compare cycle time vs takt time, and determine operator requirements.
Tap Size Calculator
Free Tap Size Calculator for cutting and forming taps — find the correct tap drill size for UNC, UNF, Metric Coarse, Metric Fine, and NPT threads with nearest standard drill bit cross-reference.
TDEE Calculator
Free TDEE (Total Daily Energy Expenditure) calculator. Estimate your daily calorie burn using 4 BMR formulas, 7 activity levels, macronutrient breakdowns, zigzag calorie cycling, and weight loss/gain targets.
Tent Capacity Calculator
Free tent capacity calculator for event tents and camping tents. Enter your guest count or tent dimensions to find the right tent size for any occasion.
Term Life Insurance Calculator
Free Term Life Insurance Calculator — estimate how much life insurance coverage your family needs using DIME, Income Multiplier, and Needs Analysis methods. Get a premium estimate instantly.
Test Score Calculator
Free Test Score Calculator — instantly convert wrong answers or points earned into a percentage score and letter grade. Supports standard and extended (A+/A-) grading scales, bonus points, a grade breakdown table, and a reverse calculator that tells you how many questions you can miss to earn a target grade.
Throughput Calculator
Free Throughput Calculator — calculate production throughput rate, cycle time, capacity utilization, and throughput time for manufacturing and operations management.
Time Duration Calculator
Free Time Duration Calculator — calculate the duration between two dates/times, add or subtract time from a date, and convert between time units like seconds, minutes, hours, days, weeks, months, and years.
Tip Calculator
Free tip calculator to quickly calculate tips, split bills between friends, and see tip amounts for different percentages.
Tons to Kg Converter
Free Tons to Kilograms (kg) converter supporting metric tons (tonne), short tons (US), and long tons (UK/Imperial). Bidirectional conversion with multi-unit output, visual comparison chart, and reference table.
Total Compensation Calculator
Free Total Compensation Calculator — add base salary, bonus, health benefits, 401(k) match, PTO value, equity, and perks to reveal your true package worth in seconds.
tPA Calculator
Free tPA (Alteplase) and Tenecteplase stroke dosing calculator. Calculate total dose, IV bolus, infusion rate, and waste volume for acute ischemic stroke treatment.
Travel Time Calculator
Free Travel Time Calculator — solve for drive time, required speed, or distance covered. Enter distance and speed to calculate how long a trip takes, add departure time for an estimated arrival, include break stops, and estimate fuel cost. Perfect for road trip planning, commuting, and logistics.
TSP Calculator
Free Thrift Savings Plan (TSP) calculator for military BRS and federal civilian FERS members. Project your retirement balance with BRS matching, catch-up contributions, fund allocations, and 4% withdrawal estimates.
URR Calculator
Free URR calculator for hemodialysis adequacy. Calculate Urea Reduction Ratio, Daugirdas spKt/V, eKt/V, UFR, and nPCR with clinical interpretation.
US Gallons to Liters Converter
Free US Gallons to Liters Converter — instantly convert US liquid gallons, Imperial gallons, and US dry gallons to liters (and back). Includes formula display, real-world reference examples, batch conversion, and a printable comparison table.
VAT Calculator
Free Value Added Tax (VAT) calculator — add VAT to a net price or remove VAT from a gross price instantly. Supports custom rates, country presets, and calculation history.
Velocity Calculator
Free Velocity Calculator — solve for velocity, distance, time, acceleration, or displacement using the four core physics equations: basic speed (v=d/t), kinematic v=u+at, kinematic v²=u²+2as, and average velocity. Supports metric and imperial units with multi-unit output.
VO2 Max Calculator
Free VO2 max calculator with 9 test protocols — Cooper 12-min run, Rockport 1-mile walk, 1.5-mile run, HR ratio, step test, beep test, Balke, Bruce treadmill, and 2000m rowing. Get ACSM fitness classification, percentile rank, fitness age, training zones, and race time predictions.
Water Intake Calculator
Free daily water intake calculator based on your weight, age, gender, activity level, and climate. Uses both TDEE-based and weight-based formulas to recommend optimal hydration.
Wedding Budget Calculator
Free Wedding Budget Calculator — plan and allocate your wedding expenses across 13 categories including venue, photography, florals, attire, and more. Compare industry benchmarks, track spending by percentage or fixed amounts, and export your budget plan.
Wordle Game
Free Wordle word-guessing game — guess the hidden 5-letter word in 6 tries. Includes daily puzzle mode, unlimited play, hard mode, colorblind mode, and share results.
Yarn Yardage Calculator
Free Yarn Yardage Calculator — estimate how many yards (or meters) of yarn you need for any knitting or crochet project. Covers hats, sweaters, blankets, socks, shawls, and more with stitch pattern multipliers and adjustable safety buffers.