Enter your age in years (13-100)
Percentage of daily calories from carbs (USDA recommends 45-65%)
Used to calculate carbs per meal
Enter Your Details
Fill in your age, sex, height, weight, activity level, and goal to see your personalized daily carbohydrate target, per-meal breakdown, fiber recommendation, and diet-type comparison chart.
How to Use the Carbohydrate Calculator
Enter Your Body Measurements
Select your preferred unit system (US or Metric), then enter your sex, age, height, and current body weight. These are used to calculate your Basal Metabolic Rate (BMR) — the calories your body needs at rest. Accurate inputs produce more accurate results, so use your current weight rather than a goal weight.
Choose Your Activity Level and Goal
Select the activity level that best describes your typical week — be honest, as overestimating activity is the most common reason people struggle to lose weight despite following a calorie target. Then choose your goal: losing 0.25 or 0.5 kg per week, maintaining your current weight, or gaining 0.5 kg per week for muscle building.
Set Your Carbohydrate Percentage
Use the carbohydrate percentage slider or input to set how much of your daily calories should come from carbs. The USDA recommends 45-65% for most adults. If you follow a specific diet plan — such as keto (5-10%), Zone (40%), or high-carb athlete diet (65%) — enter that percentage. The diet comparison chart at the bottom shows how different percentages compare for your specific calorie needs.
Review Your Full Results
Your daily carb target, fiber recommendation, per-meal breakdown, weekly total, and all goal scenarios are shown instantly. Use the diet-type comparison bars to explore how different approaches compare. For meal prepping, enter the number of meals per day to get a per-meal gram target. Optionally open Advanced Options to switch BMR formulas or use the net carbs calculator to subtract fiber and sugar alcohols from your target.
Frequently Asked Questions
How many grams of carbohydrates should I eat per day?
The right amount of carbohydrates depends on your total calorie needs, which are determined by your body size, age, sex, and activity level. For most adults, the Dietary Guidelines for Americans recommend that 45 to 65 percent of daily calories come from carbohydrates. On a 2,000-calorie diet, that equals 225 to 325 grams per day. The Institute of Medicine also sets a minimum of 130 grams per day as the amount needed to fuel brain function. However, low-carb dieters, people managing diabetes, and endurance athletes all have different requirements. This calculator personalizes these numbers to your specific calorie budget rather than using a generic target that may not match your actual needs.
What is the difference between total carbs and net carbs?
Total carbohydrates include all carbs in a food: starches, sugars, dietary fiber, and sugar alcohols. Net carbs subtract dietary fiber and some sugar alcohols from total carbs, reflecting only the carbohydrates that significantly raise blood sugar. Dietary fiber is indigestible and passes through the gut without being absorbed as glucose, so it does not trigger an insulin response in most people. Sugar alcohols like erythritol have minimal glycemic impact, while others like sorbitol and maltitol have a partial effect. Tracking net carbs is standard practice in ketogenic and low-carb diets because ketosis is driven by blood glucose and insulin levels rather than total carbohydrate grams. For general health and weight management, tracking total carbs is usually sufficient.
How accurate is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is considered the most accurate widely available formula for estimating resting energy expenditure for non-obese adults, as validated by a large review published in the Journal of the American Dietetic Association in 2005. It predicts BMR within 10 percent for most people when combined with an appropriate activity multiplier. The Harris-Benedict equation, developed in 1919 and revised in 1984, tends to overestimate calorie needs by about 5 percent on average. The Katch-McArdle equation is the most accurate when body fat percentage is known, because it accounts for lean body mass rather than total weight. All three equations are population-level estimates — individual metabolic rates can vary by up to 15 percent from predicted values due to genetics and other factors.
Should I eat fewer carbs on rest days versus training days?
Yes, carbohydrate cycling based on activity is a well-established sports nutrition strategy. On training days — especially high-intensity or long-duration sessions — muscles need more glycogen, making higher carbohydrate intake beneficial for performance and recovery. On rest days, your total energy expenditure is lower and glycogen stores are already adequate, so slightly lower carbohydrate intake (replacing some carbs with additional protein or healthy fats) is reasonable. A practical approach for active individuals is to use your moderately active TDEE as a base, then add 50-100 grams of carbs on heavy training days and subtract 30-50 grams on complete rest days. Elite endurance athletes may carbohydrate load (up to 10 grams per kilogram body weight) in the 24-48 hours before major events to maximize glycogen stores.
What carbohydrate intake is recommended during pregnancy?
During pregnancy, the Dietary Reference Intakes set by the Institute of Medicine recommend a minimum of 175 grams of carbohydrates per day, compared to 130 grams for non-pregnant adults. This higher minimum ensures adequate glucose delivery to the developing fetus and placenta, and supports the increased energy demands of pregnancy. During breastfeeding, the recommendation rises to 210 grams per day to support milk production. Women with gestational diabetes work with their healthcare team to establish tighter carbohydrate targets, typically 175-250 grams per day spread across three meals and two to three snacks to minimize blood sugar spikes. If you are pregnant or breastfeeding, always consult your obstetrician or a registered dietitian before adjusting your carbohydrate intake based on any online calculator.
How many carbohydrates do athletes need compared to sedentary people?
Carbohydrate needs scale dramatically with training intensity and volume. Sedentary individuals need approximately 3-5 grams of carbohydrates per kilogram of body weight per day. Light exercisers (30-60 minutes most days) need 5-7 grams per kilogram. Endurance athletes training 1-3 hours per day at moderate to high intensity require 6-10 grams per kilogram. Ultra-endurance athletes training more than 4 hours per day can need 8-12 grams per kilogram. This is significantly higher than standard percentage-based calculations because athletes burn far more glycogen. For example, a 70 kg runner training 2 hours daily needs approximately 420-700 grams of carbohydrates per day — values that appear extreme on standard diet plans but are appropriate for their energy demands. This calculator shows the athletic guideline range when you select a very active or extra active level.