How to use the sweat rate calculator
Compute sweat rate during exercise. Enter weight before, weight after, fluid drunk, exercise time in the fields above; the sweat rate, body mass loss are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- w1 — Weight before (kg)
- w2 — Weight after (kg)
- f — Fluid drunk (L)
- t — Exercise time (h)
Worked example
With weight before = 70.0 kg, weight after = 69.3 kg, fluid drunk = 0.5 L, exercise time = 1 h, the calculator gives sweat rate ≈ 1.2 L/h; body mass loss ≈ 1 %.
Frequently asked questions
What is the formula for the sweat rate calculation?
Sweat rate (L/h) = (w1-w2+f) / t. Body mass loss (%) = 100 × (w1-w2) / w1. Here w1 is weight before (kg), w2 is weight after (kg), f is fluid drunk (L), t is exercise time (h).
What inputs do I need for the sweat rate calculator?
You need weight before in kg, weight after in kg, fluid drunk in L, exercise time in h. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.