Carbohydrate Loading Calculator
Carbohydrate loading tops up muscle and liver glycogen before a long endurance event so fatigue arrives later. Sports-nutrition guidance commonly targets roughly 8 to 12 grams of carbohydrate per kilogram of bodyweight per day in the one to three days beforehand. Because the right figure within that range is individual, this calculator keeps the grams-per-kilogram target editable, defaulting to 10 g/kg. Enter your bodyweight and target to see daily carbohydrate grams, the approximate calories from those carbohydrates at 4 calories per gram, and a per-meal split across four meals.
Carb loading formula
Bodyweight in kg = pounds / 2.20462 (if entered in pounds)
Daily carbohydrate = bodyweight in kg * target g per kg
Carbohydrate calories = daily carbohydrate * 4
Per meal = daily carbohydrate / 4
Carbohydrate provides about 4 calories per gram (an Atwater general factor used in food labeling). The common loading range is 8 to 12 g/kg/day; this calculator defaults to 10 and lets you adjust.
Carb loading context
- Loading mainly benefits continuous endurance events lasting roughly 90 minutes or more.
- The common target range is about 8 to 12 g/kg/day for one to three days pre-event.
- Stored glycogen binds water, so a small short-term weight gain is normal.
- Carbohydrate supplies about 4 calories per gram per standard food-labeling factors.
- This tool reports targets only and is not a substitute for advice from a registered dietitian.
Carb loading: frequently asked questions
What is carbohydrate loading?
Carbohydrate loading is a strategy of eating a high-carbohydrate diet in the days before a prolonged endurance event to maximize muscle and liver glycogen stores. Fuller glycogen stores delay fatigue in events lasting roughly 90 minutes or more, such as a marathon or long triathlon.
How many grams of carbohydrate should I eat when loading?
Sports-nutrition guidance commonly cites a loading range of about 8 to 12 grams of carbohydrate per kilogram of bodyweight per day in the one to three days before the event. The exact figure is individual, so this calculator leaves the grams-per-kilogram target as an editable input with a default of 10 g/kg.
How does this calculator work?
It multiplies your bodyweight in kilograms by the carbohydrate target you choose to get daily grams, then multiplies grams by 4 to estimate calories, since carbohydrate provides about 4 calories per gram. If you enter weight in pounds, it converts to kilograms first by dividing by 2.20462.
How many calories are in a gram of carbohydrate?
Carbohydrate provides approximately 4 kilocalories per gram, one of the standard Atwater general factors used in nutrition labeling. This calculator uses 4 calories per gram to convert your daily carbohydrate grams into an approximate calorie figure.
Is carb loading right for everyone?
Carb loading mainly benefits prolonged continuous endurance events. It is not useful for short or stop-start activities and can cause weight gain from stored water. People with diabetes or other conditions should seek individual advice. This tool reports targets only and is not medical or dietary advice.
Official sources
- U.S. Food and Drug Administration: food labeling and calorie factors.
- Academy of Nutrition and Dietetics: sports nutrition guidance.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.