How to use the marathon carb loading meal split calculator
Enter your body weight and a daily target in grams per kilogram, pick the loading block and the number of eating occasions, and the tool returns the daily carbohydrate figure, the total for the whole block and the grams that land in each meal. The segment table stacks the amount and running total for each loading day, and a race duration converts the in-race hourly range into a total.
The reference figures come from the joint position of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada: 10 to 12 g per kg of body mass across the 36 to 48 hours before the race, and during the race small amounts or a mouth rinse under 1 hour, 30 to 60 g per hour for 1 to 2.5 hours, and up to 90 g per hour beyond 2.5 hours. The daily figure multiplies body mass by your entered g per kg, and the block total multiplies that by the loading days. Weight entered in pounds is converted at 2.20462 lb per kg and the converted figure is shown (checked October 2026).
A narrative plan for before, during and after the race is not an output of this page. Fluid volumes, gel counts and total calories are not covered either; only carbohydrate grams are. Loading stores water alongside the carbohydrate, so body weight often rises, and a high-fibre menu can add gut discomfort. If diabetes, kidney disease or any other condition restricts your carbohydrate intake, do not use these numbers directly without first speaking to a clinician or sports dietitian.
Frequently asked questions
The joint position of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada gives 10 to 12 g per kg of body mass over the 36 to 48 hours before the race. The result also shows that range for your weight.
It divides the daily carbohydrate target by the number of eating occasions you entered. It is an even split, so counting snacks as occasions lowers the amount in each one.
No. This page only divides loading carbohydrate into meals. It does not output fluid volumes, gel counts or total calories.