The International Society of Sports Nutrition position stand on nutrient timing recommends 30 to 90 grams of carbohydrate per hour for exercise lasting over 60 minutes, with the higher end reached using glucose-fructose gel blends. This calculator starts you at roughly 1 gram per kilogram of body weight per hour, a common practical starting point, then keeps you inside that 30 to 90g band.
Divide your total race-hour carbohydrate target by the carbs in one gel: total carbs needed is your target grams per hour multiplied by your finish time in hours. Enter your weight, finish time and carbs per gel above and the calculator runs that math for you.
Spread gels evenly across the race rather than waiting until you feel low on fuel, since glycogen depletion is hard to recover from mid-race. The schedule above spaces your gels at even kilometre or mile marks and elapsed times based on your goal pace.
Most energy gels carry 20 to 40 grams of carbohydrate per packet, with dual-carb glucose and fructose blends running toward the higher end. Check your own gel's label and enter that figure, or use the preset chips for a rough estimate.
Yes. Sports nutrition guidance recommends rehearsing your planned carbohydrate intake on training long runs before race day, since tolerance for higher carb rates is trainable and race day is the wrong time to test a new gel or a new pace of fueling.