Carbs per hour calculator
Tell us how long you will be out and how hard you will go. You get the carbohydrates per hour to aim for, plus fluid and a simple example of how to get there.
Your numbers
Tell us how long you will be out and how hard you will go. You get the carbohydrates per hour to aim for, plus fluid and a simple example of how to get there.
How many carbs per hour do you need?
It depends mostly on how long you are out and how hard you go. As a rough guide for a healthy, trained adult:
- Up to 1 hour: nothing needed during the session.
- 1 to 2 hours: about 30 to 60 g per hour.
- 2 to 3 hours: about 60 to 90 g per hour.
- Over 3 hours: up to 90 to 100 g per hour, if your gut is trained for it.
Why duration and intensity matter
Your muscles store a limited amount of carbohydrate. At a hard effort that store can be largely used up after about an hour, so longer and harder sessions need fuel on top. The calculator uses the same two inputs as the 2fuel app: how long, and how hard.
Glucose and fructose
Glucose and fructose use different routes through the gut, so a mix can be absorbed faster than glucose alone. Research varies a lot and people differ, so there is no single perfect ratio. 2fuel plans with about 1 part glucose to 0.8 parts fructose, moving towards 1 to 1 for well trained athletes. Many products use 2 to 1.
Build up slowly
Taking in 90 g per hour on the day, without practice, is a common way to end up with stomach trouble. A typical build up: 30 to 40 g per hour in long sessions first, then 60, then 75 to 90, then test your race plan in two or three hard sessions. Read the full plan in our guide on training your gut.
What this calculator cannot do
It does not know your gut, the heat, your sweat rate or how your last meal sat. It gives a sensible starting point for a healthy adult. For a plan around your own weeks, the 2fuel app calculates every session and plans your meals around it.
General information for healthy adults, not medical advice. If you have diabetes, a gut condition, an eating disorder, or take medication, talk to your doctor or a sports dietitian first.
Common questions
How many carbs per hour for a 3 hour ride?
Roughly 60 to 90 g per hour, depending on how hard you ride. Use the calculator for a number that fits your intensity. Above 60 g per hour, train your gut first.
Do I need carbs for a one hour run?
Usually not during the run itself. A session of an hour or less rarely needs fuel during the effort. Eat well before and afterwards.
What is the maximum carbs per hour?
The research points to 90 to 120 g per hour as the upper range. Some pros take in more, but that is not realistic for most people. Build up slowly and find your own ceiling.
Is this the same as the 2fuel app?
It uses the same rules for duration and intensity. The app goes further: it plans every session, your meals and your day around the numbers.
Want this planned around your own week?
The 2fuel app turns every training session into kcal, carbs per hour and protein, then into meals. With an AI coach or a sports dietitian. In beta now.