Find how much water you should drink per day based on your weight and minutes of exercise, expressed in litres and glasses.
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Enter your weight and minutes of exercise per day. We show the need in litres and glasses.
Needs rise in hot weather, pregnancy or breastfeeding, and with fever. Coffee and tea also contribute to hydration.
Water per day ≈ 2.7 L/dayInformational estimates, not medical advice. We use standard formulas (WHO, Mifflin-St Jeor, US Navy method). Instant in-browser calculation, no account, no data sent. For medical decisions, consult a professional.
Daily water need is estimated from weight, plus the water lost through exercise. A practical rule uses about 33 ml per kilogram:
For 70 kg and 30 min of exercise: 70 × 33 + 350 = 2310 + 350 = 2660 ml ≈ 2.7 litres (about 11 glasses).
A practical rule is 30–35 ml of water per kilogram of body weight. For 70 kg that is about 2.3 litres a day, plus the water lost through sweat during exercise.
Multiply your weight in kg by 33 ml and add about 350 ml for every 30 minutes of physical activity. The result estimates an ordinary day at moderate temperature.
A standard glass holds about 250 ml, so 2 litres is 8 glasses. That is where the popular “8 glasses a day” advice comes from.
Yes. Although caffeine has a mild diuretic effect, water-based drinks contribute net to hydration. Alcohol, by contrast, is dehydrating.
Yes. You lose water and electrolytes through sweat. Add roughly 350–500 ml for every 30 minutes of intense effort, and more in hot weather.
Extreme intake (over 4–5 litres in a few hours) can dilute blood sodium (hyponatremia), a dangerous condition. Drink when thirsty and spread intake through the day.
A simple sign is urine colour: pale straw yellow means good hydration, dark yellow signals you should drink more.
Yes. During pregnancy and especially breastfeeding, fluid needs rise by several hundred millilitres a day. Discuss the right amount with your doctor.
Yes. About 20% of daily water comes from food, especially fruit and vegetables such as watermelon, cucumber or oranges.