Carbs Per Hour Running Calculator

Carbs per hour running calculator. Enter your race distance and finish time to get a personalized carb target and convert it into gels and timing.

Enter your race distance and goal time to calculate your ideal carbs-per-hour target. Get a specific number you can train with and execute on race day.

Personalized carbs/hour from your race data
Works for half marathon through ultra distances
Converts your target into gels and a schedule

How to calculate your carbs per hour for running

Get a personalized carbs-per-hour number based on your race distance and goal time.

Choose your distance: Select your race distance (half marathon, marathon, or custom).
Enter your goal time: Input the finish time you are training for.
Get your number: See your carbs/hour target, total carbs, and how many gels that translates to.

Frequently asked questions

How do I calculate carbs per hour for running?

Divide your total carb target by race duration in hours. For example, 240g over 4 hours = 60g/hour. This calculator does the math for you from your finish time.

Is 60g per hour enough for a marathon?

60g/hour is a good starting point and works well for many runners. Some benefit from pushing toward 80-90g/hour with gut training and the right products.

Fueling reference

Race-day carb targets and gel counts by finish time (baseline, no body weight entered)
Race	Finish time	Carbs/hour	Total carbs	Calories	Gels
Half marathon	1:20	45 g/hr	60 g	240 kcal	2
Half marathon	1:35	45 g/hr	71 g	284 kcal	3
Half marathon	1:50	45 g/hr	83 g	332 kcal	3
Half marathon	2:05	45 g/hr	94 g	376 kcal	4
Half marathon	2:20	45 g/hr	105 g	420 kcal	4
Marathon	2:50	75 g/hr	213 g	852 kcal	5
Marathon	3:15	75 g/hr	244 g	976 kcal	5
Marathon	3:45	75 g/hr	281 g	1124 kcal	6
Marathon	4:15	75 g/hr	319 g	1276 kcal	7
Marathon	4:45	75 g/hr	356 g	1424 kcal	7
Marathon	5:15	75 g/hr	394 g	1576 kcal	7

Method and sources

The numbers on this page are computed with the same code as the TrainPace calculators, from these published methods. They are training guidance, not medical advice.

Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine 44(Suppl 1), S25–S33 — carbohydrate targets by event duration, and glucose + fructose for intakes above 60 g/hr.
Thomas, D.T., Erdman, K.A. & Burke, L.M. (2016). Nutrition and Athletic Performance (joint position statement of the ACSM, Academy of Nutrition and Dietetics, and Dietitians of Canada). Medicine & Science in Sports & Exercise 48(3), 543–568.

Other TrainPace tools

For AI agents

Every public page on this site has a Markdown mirror at the same path with a .md suffix (for example /calculator.md), and honors an Accept: text/markdown request header on the HTML URL. The calculations here are also available as callable tools through a free public MCP server — no account or API key.