Race fuel calculator
How many gels do you need?
You have the race booked and a finish time in mind. Here is how much carbohydrate to take on the way, how many gels that is, and how often to take them.
Guidance from the American College of Sports Medicine joint position statement on nutrition and athletic performance (Thomas, Erdman and Burke, Medicine & Science in Sports & Exercise, 2016), Table 2: under 45 minutes, not needed; 45 to 75 minutes, small amounts or a mouth rinse; 1 to 2.5 hours, 30 to 60 g an hour; longer than 2.5 to 3 hours, up to 90 g an hour. Read the statement. This is general guidance, not medical advice. If you have a medical condition, ask your doctor first.
Race fuel questions
How many gels do I need for a marathon?
It depends on your finish time. For a 4 h 30 min marathon, the calculator comes to 13 gels at 75 g of carbohydrate an hour if you have practised fuelling on long runs, or 8 gels at 45 g an hour if you have not. Enter your own time above for your number.
Do I need gels for a 10 km race?
Usually not. Under 45 minutes you do not need carbohydrate during the race, and between 45 and 75 minutes small amounts or a mouth rinse are enough.
How much carbohydrate is in an ANS gel?
26 g. The Apple gel has natural caffeine from guarana; the Citrus gel is caffeine-free and has 300 mg of sodium.
Should I try a new gel on race day?
No. Practise your plan on long runs first, and build up in steps of about 15 g an hour rather than jumping straight to a high target.
How many carbs do you actually need per hour? Read our guide →