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Inputs are calculated in your browser and are not sent to a server. When you use sharing, the reproducible URL includes the current conditions.
Fitness
Workout Hydration Estimator
Estimate fluid replacement from workout duration, weight, temperature, and sweat rate.
Updated: May 15, 2026
Input
Estimate workout fluid replacement from duration, weight, temperature, and sweat rate.
This applies a temperature factor to the baseline sweat rate. If your sweat rate already includes hot-condition measurement, use around 20°C to avoid double correction. Avoid overhydration.
Result
960 ml
Fluid estimate
240 ml
Per 15 min
1.37%
Body mass loss
1.2x
Heat factor
Use this as a guide and adjust for your real conditions.
Share this tool
How to use
- Enter Duration, Weight, Temperature, Sweat rate.
- Check the estimate in the result area.
- Share a reproducible URL if needed.
How to read the result
- Read Fluid estimate, Per 15 minutes as quick decision-making estimates.
- Do not treat the result as a fixed answer; adjust assumptions to see the range when needed.
Useful tips
- Useful when you want to plan fluids for a hot run; adjust inputs to compare scenarios.
- Useful when you want to estimate replacement from sweat rate; adjust inputs to compare scenarios.
- Sweat rate varies widely. Pair this with body-weight change or urine color, and avoid overhydration.
- Use results as training guides and adjust for condition, heat, surface, and fatigue.
- If the result feels too demanding, reduce distance, intensity, or duration and recalculate.
Calculation
The tool calculates training estimates from distance, time, and heart-rate inputs.
Notes
- Adjust for your condition and environment.
- This is not medical or coaching advice.
- Stop exercising if you feel pain or discomfort.
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FAQ
Are results exact?
Use results as everyday estimates. For exact decisions, confirm with official or specialized sources.
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