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

Other TrainPace tools

For AI agents

Every 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.