Sweat Rate
Calculator
Results
- Sweat rate
- 1.2
Results
| Sweat rate | 1.2 |
formula-map diagram
- Sweat rate
- 1.2
Diagram
Formula
rate = (Δweight + intake) ÷ hours= 1.2
Note
This is a simplified sports-science model for general guidance, not medical or coaching advice.
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See all →Frequently asked questions
How is sweat rate calculated from a workout?+
It's based on your body weight before and after exercise, plus any fluid consumed during the session, corrected for exercise duration: (pre-weight − post-weight + fluid intake) ÷ time. The result is typically expressed in liters per hour.
Why do I need to weigh myself before and after exercise for this?+
Weight loss during exercise, once you account for fluids drunk, is almost entirely water loss through sweat, since fat and glycogen burning contribute negligible weight change over a single session. This makes body weight change a practical proxy for fluid loss without needing lab equipment.
Does sweat rate stay the same in different weather or intensities?+
No, sweat rate rises substantially in heat, humidity, and higher exercise intensity, so a rate measured on a cool easy day won't apply to a hot hard session. It's best to test sweat rate under conditions similar to your upcoming event.
How do I use my sweat rate to plan hydration during exercise?+
Once you know your hourly sweat rate, you can aim to replace a meaningful fraction of that fluid loss during exercise, since replacing 100% is often impractical and unnecessary for shorter efforts. Losing more than about 2% of body weight in fluid, however, starts measurably impairing performance.
Why might two people doing the identical workout have very different sweat rates?+
Sweat rate varies enormously between individuals due to body size, fitness level, heat acclimation, and genetics, so there's no universal number that applies to everyone. This is exactly why the calculation is done individually rather than using a population average.