---
title: "Carbs Per Hour for Running - Marathon & Half Calculator | TrainPace"
description: "Carbs per hour running calculator. Estimate a realistic carb target for marathon or half marathon fueling (60-90g/hr) based on your finish time."
url: https://trainpace.com/fuel/carbs-per-hour-running
---

# Carbs Per Hour for Running

Carbs per hour running calculator. Estimate a realistic carb target for marathon or half marathon fueling (60-90g/hr) based on your finish time.

Carbs/hour is the simplest "fueling dial" you can turn. The right target depends on duration, intensity, and gut training.

- 60-90g/hr targets (adjustable)
- Total carbs + gel estimate
- Practical, race-day friendly guidance

## How to choose carbs per hour for a race

Estimate a carbs-per-hour target and convert it into gels and timing.

1. Choose race duration: Longer races typically benefit from more consistent fueling.
2. Pick a target range: Start with 60g/hr and progress toward 90g/hr if tolerated.
3. Practice in training: Use long runs to train your gut and confirm products.

## Frequently asked questions

### Is 90g/hr too much?

For some runners, yes. For others (with gut training and proper products), it's very doable. Start lower and practice.

### Does body weight change carb needs?

Weight matters less than duration and intensity for carbs/hour. Tolerance and practice matter most.

- [Calculate Carbs/Hour](https://trainpace.com/fuel)

## 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

- [Pace Calculator](https://trainpace.com/calculator) — training paces from a recent race result
- [VDOT Calculator](https://trainpace.com/vdot) — fitness score and equivalent race times
- [Training Plan Builder](https://trainpace.com/plan) — week-by-week 5K to marathon plans
- [Race Fuel Planner](https://trainpace.com/fuel) — carbs per hour and gel counts
- [Elevation Finder](https://trainpace.com/elevation-finder) — GPX route and climb analysis

## 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.

- [llms.txt](https://trainpace.com/llms.txt) — site index for agents
- [llms-full.txt](https://trainpace.com/llms-full.txt) — every page's Markdown in one file
- [MCP server docs](https://trainpace.com/mcp) — endpoint, tools, and client setup