Water Intake Calculator by Weight
The simplest way to estimate your daily water need is from your body weight — roughly 30–35 ml per kg, adjusted for how active you are and how hot it is. Enter your weight, activity and climate to get your target in litres. Heavier and more active people need more; hot Indian summers push the number up further.
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Frequently asked questions
How much water per kg of body weight?+
About 30–35 ml per kg per day is a common guide — so a 60 kg adult needs roughly 1.8–2.1 litres, before adding extra for exercise and heat. The calculator applies this and adjusts for your activity and climate.
Should heavier people drink more water?+
Generally yes — a larger body has more tissue and loses more fluid, so water needs scale with weight. That's why a weight-based estimate is more useful than a flat 'eight glasses' figure.
How much water should I drink a day?+
A common guide is about 30–35 ml per kg of body weight — roughly 2–3 litres for most adults — adjusted up for activity and hot weather. The calculator personalises this from your weight, activity level and climate. Thirst and pale-yellow urine are good everyday signals you're well hydrated.
Does the '8 glasses a day' rule apply to everyone?+
It's a rough average, not a rule. Your real need depends on body size, activity, climate, pregnancy and health. In India's hot months you'll need more. Use the calculator for a personalised figure rather than a fixed number of glasses.
Do tea, coffee and food count toward hydration?+
Yes. Around 20% of your fluid typically comes from food, and tea and coffee do count despite their mild diuretic effect. The calculator estimates total water need; you don't have to get all of it from plain water.
Can you drink too much water?+
Rarely, but yes — drinking far more than you need can dilute blood sodium (hyponatraemia), which is dangerous. This mostly affects endurance athletes overdrinking. For most people, spreading normal intake through the day is safe.