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Water Intake Calculator

Find how much water you should drink each day.

Last updated: 8 Aug 2026

Quick answer

A common guideline is about 33 ml of water per kg of body weight per day, plus more for exercise. For example, a 70 kg person needs roughly 2.3 litres a day, plus about 350 ml per 30 minutes of activity. Enter your weight and activity above to get your target.

Staying hydrated supports energy, focus and health. This water intake calculator estimates your daily target from your body weight and activity, using the common guideline of about 33 ml per kg plus extra for exercise.

How to calculate your daily water intake

  1. 1 Enter your body weight in kilograms.
  2. 2 Enter your daily exercise time in minutes.
  3. 3 We apply ~33 ml per kg plus ~350 ml per 30 minutes of activity.
  4. 4 See your daily target in litres and glasses.

Frequently asked questions

How much water should I drink a day?
A common guideline is about 33 ml per kg of body weight, so roughly 2–3 litres for most adults, plus more when you exercise or in hot weather.
Does food and tea count?
Yes — food and other beverages contribute to hydration, but plain water is the best primary source.
Can I drink too much water?
Very rarely; excessive intake in a short time can dilute blood sodium. Spread your intake through the day.

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