Marathon Fueling Calculator
Plan race-day carbohydrate and gels from body weight and expected finish time.
Quick answer: enter your details below and click Plan My Fueling — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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Enter your details below.
How to use
- Enter your expected race time in hours.
- Enter the carbohydrate per gel you use.
- Click Plan My Fueling.
About this tool
Enter your weight and expected race duration in hours. The tool plans carbohydrate at a typical range of 60 to 90 grams per hour for longer races and converts it into gels. This is a general planning guide, not medical or sports-nutrition advice: practise any plan in training first.
Frequently asked questions
Should I eat this much in my first marathon?
Build up gradually in training; jumping straight to 90 grams per hour can upset the stomach.
Does weight change the target?
This plan uses time, not weight, because gut tolerance and duration drive race-day carbohydrate needs.