Half Marathon Fueling Plan Calculator

Half marathon fueling plan calculator. Estimate gels needed, carbs/hour targets, and a simple schedule based on your finish time and preferences.

Fueling matters in the half marathon too. A small, consistent plan can keep effort steady and prevent late-race fade.

Gel estimate for 60-120 minutes
Carb targets and simple schedule
Adjusts for your finish time

How to plan half marathon fueling

Use your goal time to estimate gels needed and a simple fueling schedule for race day.

Select Half: Choose Half Marathon in the fuel planner.
Enter finish time: Use your goal time (or a recent race time).
Use the schedule: Follow the timing guidance and adjust based on what you practiced.

Frequently asked questions

Do I need gels for a half marathon?

It depends on duration and intensity. Many runners benefit from 1-2 gels, especially if racing hard for 90+ minutes.

Can I fuel with sports drink only?

Sometimes. If your drink provides enough carbs and you can carry it, you may not need many gels.

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

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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.