Calculate how much water to drink per day based on body weight, exercise and climate — in litres and glasses. Free, instant, no sign-up.
How water intake is estimated
A common guideline is 30–35 ml of water per kilogram of body weight per day (this calculator uses 33 ml/kg), plus extra for exercise — roughly 350 ml per 30 minutes — and hot climates. Food typically covers about a fifth of total fluid needs on top of this.
Water ≈ 33 ml × weight (kg) + 12 ml × exercise min + 500 ml if hot climateFrequently asked questions
Does coffee or tea count?
Mostly yes. Caffeinated drinks are mildly diuretic but still hydrate on balance. Water remains the best default since it adds no sugar or calories.
Can I drink too much water?
Yes — excessive intake in a short time can dilute blood sodium (hyponatremia), which is dangerous. Spread intake through the day and drink to thirst during long exercise. This is general information, not medical advice.
Do I need exactly this amount every day?
No. Needs vary with diet, sweat rate and health conditions. Pale-yellow urine is a practical everyday indicator of good hydration.
Last updated: 7 July 2026
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For information only — not medical advice. HealthMint · MintKit