Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Running
Marathon Fueling Calculator
Calculates how many grams of carbohydrates you need during a marathon or long race based on body weight, expected finish time, intensity, and weather. Use it during race planning to build your on-course nutrition strategy.
Fill in the required fields to see your result.
Running
Running Hydration Calculator
Estimates how many ounces of fluid a runner needs during a run based on body weight, duration, temperature, and intensity. Use it before long runs or races to plan your hydration strategy and avoid dehydration.
Fill in the required fields to see your result.
Key differences
| Marathon Fueling Calculator | Running Hydration Calculator | |
|---|---|---|
| Category | Running | Running |
| Inputs required | 4 | 4 |
| Result | Total Carbs Needed (grams) | Recommended Fluid Intake (fl oz) |
| What it does | Calculates how many grams of carbohydrates you need during a marathon or long race based on body weight, expected finish time, intensity, and weather. Use it during race planning to build your on-course nutrition strategy. | Estimates how many ounces of fluid a runner needs during a run based on body weight, duration, temperature, and intensity. Use it before long runs or races to plan your hydration strategy and avoid dehydration. |