Sweat Rate Calculator
How much you should drink during exercise.
48 oz/hour
Total sweat lost
48 oz
Drink target (70%)
34 oz/hr
Body weight lost/hr
2.00 lb/hr
Total sweat = (before - after) + fluid drunk. The 70% replacement target is the Gatorade Sports Science Institute guideline for matching most of the loss without overdrinking. Replace fully after the session.
About
Weigh yourself before and after a hard workout. The difference (plus what you drank) is what you sweat out. Multiplied to per-hour, it tells you a baseline replacement rate for hot or long efforts.
How to use
- Weigh yourself before and after the session.
- Enter how long you worked out and how much you drank.
- See sweat rate per hour and your replacement target.
FAQ
Should I always replace 100%?+
Not during. Aim for 70-80% of sweat lost during the activity. Top off with the rest after.
What about salt?+
If you're a salty sweater (white residue on shirts), add electrolyte tabs in long efforts. Plain water is fine for under 60-90 minutes.