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NUTRITION & PHYSIOLOGY
Sweat Rate
Calculator v1.0
Estimate your hourly sweat rate by comparing pre- and post-exercise body weight,
accounting for fluid intake during the session. Use the results to plan your hydration
strategy for training and racing.
Results
Sweat Rate
1,300 ml/hr
hourly fluid loss
Total fluid lost
1,300 ml
Body weight lost
1.14%
Dehydration status
Mild dehydration
Aim to drink 325 ml every 15 minutes during exercise.
| % Body Weight Lost |
Status |
| < 1% | Well hydrated |
| 1 – 2% | Mild dehydration |
| 2 – 3% | Moderate dehydration |
| 3 – 4% | Significant dehydration |
| > 4% | Severe dehydration |
Methodology
Total fluid lost = (Pre-weight − Post-weight) × 1000 + Fluid consumed
Sweat rate = Total fluid lost ÷ (Duration ÷ 60)
% Body weight lost = (Pre-weight − Post-weight) ÷ Pre-weight × 100
Weight change is assumed to represent fluid loss only. For best accuracy, weigh yourself
nude or in dry clothing before and after exercise, and account for any urination during the session.
The 15-minute drinking recommendation divides the hourly sweat rate into four equal portions.
Changelog:
v1.0 — Initial release. Pre/post weight to hourly sweat rate, dehydration status, and personalised hydration plan.