Tools · Fuel
Carbs per hour calculator
How much carbohydrate to take during a session, from how long it lasts and how hard it is. For long runs, rides, races and HYROX.
During the session
Enter the session length to see your range.
Educational, not medical advice. If you have diabetes, a heart condition or another medical condition, ask your doctor or a dietitian first.
How it works.
The ranges come from the sports nutrition guidelines (the 2016 joint position statement of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada): nothing needed under 45 minutes, small amounts up to 75, 30–60 g an hour up to two and a half hours, and up to 90 g an hour beyond that.
Intensity sets where you sit in the range. An easy session runs more on fat and needs less; a hard one or a race needs the top of it. The guidelines are for healthy adults in endurance training. Your gut, the heat and the day’s food all change what works, so try it on long sessions first.
px sets this for you each day: the food follows the session it is planned around, and moves when the session does.
Sources
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543–568.
- Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med. 2014;44(Suppl 1):S25–S33.
From px Insights
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Questions
How many carbs per hour for a marathon?
For a marathon over two and a half hours, 60–90 g an hour, with a glucose and fructose mix above 60 g. Faster runners sit in the 30–60 g band. Start lower and build up over your long runs: the gut adapts with practice.
Do I need carbs on an easy run?
Under 75 minutes, usually not. On longer easy sessions the bottom of the range is usually enough. Hard sessions and races are where carbohydrate during exercise pays off most.
How much for HYROX?
Most HYROX races take between one and two hours, which puts them in the 30–60 g an hour band. A sports drink or gel before the start and another around halfway covers it for most people.
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