Race Day Fueling Schedule Calculator
Build a gel-by-gel carbohydrate plan for race day from your finish time and target carb intake, with the exact timing between each fuel.
How it works
Total carbs = rate (g/hr) × hours · Gels = total ÷ carbs per gel · Interval = (carbs per gel ÷ rate) × 60 min
For efforts beyond about 90 minutes, running out of carbohydrate is the main limiter, so races are won and lost on fueling. The body can absorb roughly 60 g of carbohydrate per hour from a single sugar source, or up to 90 g or more with mixed glucose-and-fructose products and a trained gut. This tool spreads your target intake evenly across the race rather than in a few big hits, which keeps blood sugar steady and the stomach settled.
Worked example
A 3:30 race at 60 g/hr needs 60 × 3.5 = 210 g of carbohydrate. With 22 g gels that is about 10 gels, one every (22 ÷ 60) × 60 ≈ 22 minutes, supplying roughly 840 kcal.
Frequently asked questions
How many carbs per hour should I target?
Start at 30–60 g/hr for most runners. Only push toward 90 g/hr or more if you have practised it in training with glucose-fructose products, since the gut needs to be trained to absorb that much.
Should I start fueling right away?
Begin within the first 30–45 minutes rather than waiting until you feel low. Once glycogen runs down it is very hard to catch up mid-race, so fuel early and steadily.
What about drinks and real food?
Any carbohydrate source counts toward the total — sports drinks, chews, bananas and gels. Just add up the grams per hour; the schedule here works whatever the source.
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This calculator is for educational purposes. Double-check important results before acting on them.