Free hydration calculator: enter your weight, activity minutes and weather to estimate a daily water reference in millilitres and ounces. Estimate only. 100% Local
How to Use the Hydration Calculator
Enter your weight, daily exercise minutes and weather, and press Estimate Water. The result updates as you type.
How it works
The baseline is about 35 ml per kilogram of body weight.
Exercise adds roughly 8 ml per active minute; hot weather adds about 10%.
Rounded to the nearest 10 ml, with the ounce figure alongside.
Features
Daily water reference in millilitres and ounces
Adjusts for exercise minutes and weather
Rounded, easy-to-read output
All processing runs locally in your browser. Your data is not uploaded to any server.
This is a general reference estimate, not medical advice.