Carbs-Per-Hour Calculator
The 30/60/90 rule is a starting point, not your number. Get your personal grams-per-hour from your weight, effort and race length — and the carb type your gut actually needs.
*Based on ACSM/ISSN and Jeukendrup's multiple-transportable-carb research. The number is a target to train toward, not to force on race day cold — practise it on long runs first.
Build the engine the fuel feeds
Carbs power the work — but only if the training's there. The free assessment builds the plan your fueling supports.
Find your Hybrid Level →Common questions
How many carbs per hour should I take running?
It depends on how long and hard you're going. Under an hour you often need nothing; one to two hours, 30–60 g/h; standard endurance two hours and up, 60–90 g/h; and only gut-trained athletes push toward 120 g/h. Enter your race above for your personal number in that range.
What's the difference between 60 and 90 grams of carbs an hour?
Your gut can only absorb about 60 g/h of a single carbohydrate like glucose — that's a hard ceiling set by one transporter. To go higher you need to add fructose, which uses a second transporter, so a glucose:fructose blend (classically about 2:1) lets you absorb up to ~90 g/h and beyond.
Can I really absorb 120 g of carbs an hour?
Some athletes can, but only after deliberately training their gut over four to six weeks of progressively higher intake on long runs. It's not a number to attempt cold on race day — pushing 120 g/h without that adaptation is a reliable way to buy yourself GI distress mid-race.