Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
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.
Running
Running Heat Index Calculator
Estimate how much to slow your easy run pace on hot, humid days to maintain equivalent effort and avoid heat illness. Enter temperature, humidity, your normal pace, and heat acclimation level to get your adjusted target.
Fill in the required fields to see your result.
Key differences
| Running Hydration Calculator | Running Heat Index Calculator | |
|---|---|---|
| Category | Running | Running |
| Inputs required | 4 | 4 |
| Result | Recommended Fluid Intake (fl oz) | Adjusted Pace (min/mile) |
| What it does | 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. | Estimate how much to slow your easy run pace on hot, humid days to maintain equivalent effort and avoid heat illness. Enter temperature, humidity, your normal pace, and heat acclimation level to get your adjusted target. |