About the Sweat Rate Calculator
What is the Sweat Rate Calculator?
Knowing your sweat rate tells you how much to drink during training and matches, especially in Indian heat. Weigh yourself before and after a session; each kilogram lost is about a litre of sweat not replaced.
The calculator adds back what you drank, subtracts any urine, and shows your hourly sweat rate and dehydration level.
How to use the Sweat Rate Calculator
- Weight Before Exercise (kg) (sample: 72)
- Weight After Exercise (kg) (sample: 71)
- Fluid Drunk During Exercise (litres) (sample: 0.8)
- Urine Passed During Exercise (litres) (sample: 0)
- Exercise Duration (minutes) (sample: 60)
- Press Calculate Sweat Rate (results also refresh as you type). The result card shows the Sweat Rate, along with Total sweat loss, Body weight lost, Status and Drink per hour to stay under 2% loss.
Formula used
Sweat rate = (Pre-weight − Post-weight + Fluid drunk − Urine) ÷ Hours
- Dehydration = (pre-weight − post-weight) ÷ pre-weight × 100
- Rehydration = about 1.5 litres per kg lost
Losing more than 2% of body weight usually impairs performance.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Weight Before Exercise (kg) | 72 |
| Weight After Exercise (kg) | 71 |
| Fluid Drunk During Exercise (litres) | 0.8 |
| Urine Passed During Exercise (litres) | 0 |
| Exercise Duration (minutes) | 60 |
| Result | Value |
|---|---|
| Sweat Rate | 1.8 litres/hour |
| Total sweat loss | 1.8 litres |
| Body weight lost | 1.39% |
| Status | Under 2% – hydration was adequate |
| Drink per hour to stay under 2% loss | 0.36 litres |
| Fluid to drink afterwards (1.5 L per kg lost) | 1.5 litres |
Tips for using the Sweat Rate Calculator
- Weigh with minimal clothing and towel off sweat before the post-exercise weigh-in.
- For sessions over an hour or heavy sweating, add electrolytes (sodium) to your drink.