Outdoor & Adventure

Free Backpack Weight Calculator — calculate your pack's base weight, total weight, Big Three breakdown, and weight-to-body ratio in lbs and kg. Includes gear checklist for every category, consumable estimators, and weight reduction tips.

Free Bike Frame Size Calculator — find your perfect bicycle frame size using height and inseam length for road, mountain, hybrid, and kids bikes.

Free Bow Draw Weight Calculator — find your actual draw weight at your personal draw length, get archer-profile recommendations, and calculate arrow kinetic energy and hunting suitability.

Free Bullet Drop & Ballistic Trajectory Calculator — compute drop, wind drift, velocity, energy, and time of flight at any range with G1/G7 drag models, atmospheric corrections, and DOPE card export.

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.

Free Cycling Power Output Calculator — compute required watts from speed, or find achievable speed from power, using real physics (gravity, aerodynamic drag, and rolling resistance).

Free Elevation Gain Calculator — calculate total elevation gain, grade percentage, difficulty scores, energy miles, and calories burned for hiking, running, and treadmill workouts.

Free Fish Weight Estimator — estimate the weight of your catch using species-specific formulas. Supports 30+ freshwater and saltwater species with length + girth or length-only calculations, body condition scoring, relative weight (Wr) index, trophy comparison, and catch log with CSV export.

Free Fishing Line Strength Calculator — convert between PE number, diameter, monofilament, and braided line ratings. Includes knot strength estimator, species recommendations, line condition factor, and safe working load.

Free Game Meat Yield Calculator — estimate boneless meat yield, freezer space, servings, and cost savings from any big game animal including deer, elk, moose, bear, and more.

Free World Handicap System (WHS) Golf Handicap Index calculator. Enter up to 20 rounds to compute your official Handicap Index, Course Handicap, Playing Handicap, and score differentials — with trend chart, round history, and CSV export.

Free Hike Time Estimator — calculate hiking time using Naismith's Rule, Book Time, Tobler's Function, Langmuir, and Tranter corrections. Supports multi-segment routes, terrain, fitness, pack weight, weather, and group adjustments.

Free Hiking Calorie Calculator — estimate calories burned hiking based on your body weight, pack load, distance, elevation gain, terrain type, altitude, and temperature. Includes multi-day trip planner and food weight estimator.

Free Kayak Size Calculator — find the right kayak length, width, weight capacity, and hull volume for your height, weight, kayak type, and paddling style.

Free Marathon Pace Calculator — calculate your required pace from a target finish time, generate per-mile and per-km split tables, predict race times across distances using Riegel's formula, and get VDOT-based training zones.

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.

Free Scuba Dive Time Calculator — plan your dives with no-decompression limit (NDL) calculations using the PADI recreational dive table with interpolation, surface air consumption (SAC) and respiratory minute volume (RMV) analysis from completed dive data, gas planning with Rule of Thirds reserve allocation showing maximum dive time and gas supply breakdown, and comprehensive nitrox tools including maximum operating depth (MOD), equivalent air depth (EAD), partial pressure of oxygen (PO2) safety assessment, and best mix recommendations. Supports metric (metres, bar, litres) and imperial (feet, psi, cubic feet) units, saltwater and freshwater density adjustments for accurate ambient pressure calculations using Boyle's law, and three conservatism levels (normal, conservative, very conservative). Features visual NDL consumption gauge, breathing rate classification scale, Rule of Thirds stacked bar chart, PO2 colour-coded safety gauge, preset tank sizes for common cylinders, quick depth buttons, CSV dive plan export, and print-friendly summaries.

Free ski binding DIN setting calculator based on the ISO 11088 standard. Enter your weight, height, age, boot sole length, and skier type to get your recommended DIN release value.

Free Ski Length Calculator — find your ideal ski length in seconds. Enter your height, weight, ability level, and terrain preference to get a personalized ski size recommendation with waist width, flex, and rocker profile guidance.

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.

Free Snowboard Size Calculator — find your perfect board length (cm), waist width (mm), stance width, binding angles, flex rating, and rocker profile based on your height, weight, boot size, riding style, and ability level.

Free Surfboard Size & Volume Calculator — find your ideal surfboard volume, length, width, and thickness based on your weight, skill level, fitness, age, and wave type.

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.

Free Trail Distance Calculator — measure multi-segment hiking routes, estimate hiking time using Naismith's Rule, Book Time, and Tobler's function, calculate calories burned, difficulty rating, effective distance, and pace for any hike or snowshoe outing.