Carb Loading Calculator: free race week carbs calculator.
Enter your weight and race length. Get your carbs per day before the race, and an example day of meals.
Carb loading
A 3 h 30 min race
Carbs a day
700 to 840g
10 to 12 g per kg of body weight, for the 36 to 48 hours before the start.
Burke 2011ACSM 2016How long
2days before
Races over 90 minutes. No depletion phase needed.
An example day at about 770 g
- Breakfast189 g1.5 × Plain bagel, medium, 1.5 × Orange juice, 1 cup, 1.5 × Banana, medium, 1.5 × Honey, 1 tablespoon
- Snack83 g1.5 × Sports drink, 500 ml, 2.5 × Rice cakes, 2
- Lunch200 g3 × Cooked white rice, 1 cup, 2.5 × White toast with jam, 1 slice
- Snack86 g1.5 × Banana, medium, 1.5 × Sports drink, 500 ml
- Dinner185 g3 × Cooked pasta, 1 cup, 1.5 × Baked potato, medium
- Evening41 g1.5 × Oatmeal, 1 cup cooked
Carbs per portion are approximate (USDA FoodData Central). Your AI can swap in foods you like.
Hand it to your AI
Your AI can check these numbers against your training and adjust them. The prompt has your results filled in.
See the prompt
I'm racing for about 3 h 30 min and weigh 70 kg. A carb loading calculator based on Burke 2011 and the ACSM 2016 position stand says 10 to 12 g of carbs per kg a day for the 36 to 48 hours before: 700 to 840 g a day. Build my meals for the two days before the race around foods I like and my usual training, low in fiber and fat, and tell me what to eat on race morning.
Gemini, Grok Bot, Dots, Muse and Cue: copy the prompt and paste it in.
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How it works
How the Carb Loading Calculator works.
Carb loading fills your muscles with glycogen before a long race. For races over 90 minutes, the research says 10 to 12 g of carbohydrate per kilogram of body weight a day, for the 36 to 48 hours before the start.
For shorter races you don't need to load. Eating 7 to 12 g per kilogram in the 24 hours before is enough to start with full stores.
Most athletes find this harder than they expect, because it is a lot of carbohydrate. Lower fiber choices like white rice, pasta, bagels, juice and sports drink make it easier on the stomach. Keep fat and protein moderate on those days so the carbs fit.
The formula
- race over 90 min: 10 to 12 g × body weight (kg) a day, for 36 to 48 h
- shorter race: 7 to 12 g × body weight (kg), in the 24 h before
The science
Where the numbers come from.
Every number on this page links to the paper it comes from. How Memory.fit uses the science
Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Sciences 29(sup1):S17-S27.
Review · 2011 · doi:10.1080/02640414.2011.585473
Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance (2016). Medicine & Science in Sports & Exercise 48(3):543-568.
Position stand · 2016 · doi:10.1249/MSS.0000000000000852
Example
A worked example.
A 70 kg marathoner aiming for 3:30.
- 13:30 is well over 90 minutes, so the loading range applies: 10 to 12 g per kg.
- 270 kg × 10 to 12 g = 700 to 840 g of carbs a day, about 770 g in the middle.
- 3Spread over the two days before the race: three meals and three snacks of rice, pasta, bagels, bananas, juice and sports drink.
Questions
Carb Loading Calculator: questions.
The research says 36 to 48 hours, so start two days before the race. The old week long depletion and loading routine isn't needed for trained athletes.
10 to 12 g per kilogram of body weight a day for races over 90 minutes. For a 70 kg athlete that is 700 to 840 g a day.
The scale often goes up a little, because your body stores glycogen with water. That is fuel and fluid for the race, not fat.
For a race under 90 minutes, no. Eat a carb rich day before, 7 to 12 g per kg, and a good breakfast. A half marathon over 90 minutes can benefit from a short load.
Foods that are high in carbs and low in fiber and fat: white rice, pasta, bagels, white bread with jam, potatoes, bananas, juice and sports drink. Stick to foods you know.
Not medical advice. These numbers come from published research on groups of athletes. Your own needs can differ; talk to a doctor or a sports dietitian about any health condition.