Health & Fitness
Water Intake Calculator
Estimate daily water intake from body weight, with extra for exercise.
This result is an estimate of daily water intake in litres, split into a base amount from body weight and an extra amount from exercise.
Formula
Base water is about 33 ml per kilogram of body weight, plus about 12 ml per minute of exercise.
How it works
Body weight sets the base amount, and exercise minutes add a small extra allowance. Hot weather, illness and heavy sweating all push real needs higher than this baseline.
Worked example
For example, a weight of 70 kg gives a base of 70 × 33 = 2310 ml (2.31 litres), and 30 minutes of exercise adds 30 × 12 = 360 ml (0.36 litres), giving an estimated daily total of 2.67 litres.
FAQs
Does food count towards water?
Yes. Soups, fruit and vegetables all contribute fluid.
Is there a risk of drinking too much?
Very high intakes in a short time can be harmful; spread intake through the day.
Do I need exactly this amount?
No. Thirst, urine color and conditions matter too.
General information only, not medical advice.
Related calculators
Bedtime From Wake Time Calculator
Instant result, no sign-up.
All tools are free.
Each page shows the formula it uses, so you can check the result yourself.
Built for phone browsers.
Start with a free calculator
Search, pick a calculator, and get an instant result. No sign-up, no download.