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Water Intake Calculator
Estimate a daily water target from your body weight, exercise time and climate.
Daily water target
Daily target: —
In 250 ml cups: —
From body weight: —
Exercise and climate: —
How to use the Water Intake Calculator
- Enter your body weight in kilograms.
- Add how many minutes you exercise on a typical day.
- Pick your climate and read the daily water target.
Features
- Uses roughly 35 ml of water per kilogram
- Adds an allowance for exercise minutes
- Climate adjustment for hot weather
- Runs locally, no uploads
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Frequently Asked Questions
Common questions about the free online water intake calculator.
A common guide is about 35 millilitres per kilogram of body weight, so a 70 kilogram adult
starts near 2.5 litres before exercise.
The tool multiplies your weight by 35 millilitres, adds about 400 millilitres for each 30
minutes of exercise, then adjusts for climate.
Yes. Sweating during training loses fluid, so the calculation adds an allowance based on how
many minutes you exercise each day.
Yes. Heat and humidity raise sweat losses, so choosing the hot option adds about fifteen
percent to the daily target.
Yes. The cup figure uses a 250 millilitre cup, a common kitchen measure that is close to
eight fluid ounces.
Around twenty percent of daily fluid usually comes from food and other drinks, so you need
not drink the whole amount as plain water.
Rarely, but drinking far more than you need can dilute blood sodium. Spread your intake
through the day rather than in one go.
No. Children, pregnant women, older adults and people with heart or kidney conditions need
individual advice from a professional.
No. The target is an estimate for general information and not medical advice, so follow your
doctor if you have a health condition.
Last updated: October 10, 2026