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Hydration Calculator — Fluid Intake for Cycling
Calculate fluid intake requirements based on duration and temperature.
How We Calculate This
Hydration Estimation
- Fluid per hour = Base sweat rate × Body weight × Intensity factor × Temperature factor
- Total fluid = Fluid per hour × Duration
- Bottles needed = Total fluid / Bottle size
Frequently Asked Questions
Most riders need 500-1000 ml per hour depending on intensity and temperature. In hot conditions this can rise to 1000-1500 ml/hr. Aim to replace 60-80% of sweat losses.
For rides over 90 minutes, add electrolyte mix to your bottles. Sodium is the most important electrolyte lost through sweat.
Yes, overhydration (hyponatremia) is a real risk, especially on long rides. Do not force fluid beyond comfort. A good guide is to drink to thirst and ensure some sodium intake.
A standard bike bottle is 750 ml. Large bottles are 800-950 ml. Most bottle cages fit both sizes.
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Last updated: February 2026
All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.