Race Nutrition Calculator
Carbs, fluid and sodium per hour from your weight, pace and distance.
Conditions
How is this calculated?
Duration comes from your distance and pace. Carbs follow duration (little or none under 75 min, 30–60 g/h up to 2.5 h, up to 90 g/h after that) and are adjusted for weight and pace. Fluid starts from 6–8 ml/kg/h, shifted by pace and weather. Sodium is estimated at about 500 mg per liter.
Estimated duration
1:55:56
13.1 mi · 8:51 min/mi
Carbohydrates
56 g/ h
108 g total
range 30–60 g/h · ~4.5 25 g gels
Hydration
489 ml/ h
945 ml total
range 416–562 ml/h · ~2 500 ml bottles
Sodium
244 mg/ h
471 mg total
range 147–293 mg/h
General ranges based on ACSM guidance and Jeukendrup's work. Sweat rate and gut tolerance differ: rehearse your plan in training, not on race day.
Frequently asked questions
How many carbs per hour during a race?
Under 45 minutes, fueling is usually unnecessary. Between 1 h and 2.5 h, most runners aim for 30 to 60 g of carbohydrate per hour. Beyond that, up to 90 g/h is possible if the gut has been trained, using a glucose + fructose mix. The calculator places your target inside that range from your weight and pace.
How to estimate hydration needs?
A common range is 400 to 800 ml per hour, about 5 to 10 ml per kilogram. Heat, humidity and sweat rate move that number. Weigh yourself before and after a run: each kilogram lost is about 1 liter of sweat.
Should I eat during a 10K?
A 10K often lasts under an hour. Carbohydrate fueling is not required. A sip of water is enough for many runners, more if it is hot. Save gels for the half marathon, the marathon and long runs.
How many carbs are in a gel?
Most gels provide 20 to 25 g of carbohydrate. A 500 ml sports drink often provides 30 to 40 g. The calculator counts 25 g gels and 500 ml bottles so the total becomes a practical number of portions.