Water Intake Calculator
How much water to drink a day for your weight and activity
Your Daily Water
- 1Enter your weightIn kg or lb
- 2Add exercise and weatherAnd pregnancy if relevant
- 3See your daily waterIn litres and glasses
How much water do you need?
A common guide is about 35 ml of water for every kg of body weight, plus more for exercise, heat and when pregnant or breastfeeding. Food provides some water too.
Water (ml) = weight (kg) × 35 + exercise minutes × 12
+ 500 ml in hot weather · + 300 ml pregnant · + 700 ml breastfeeding
Signs you're drinking enough
Pale yellow urine and rarely feeling thirsty are good signs. Dark urine, headaches, tiredness and dizziness can mean you need more, especially in Indian summers.
Don't overdo it
Drinking far more than you need, very quickly, can be harmful. People with kidney or heart conditions may be told to limit fluids; follow your doctor's advice.
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Frequently asked questions
Is 8 glasses a day right for everyone?
It's a rough average (about 2 litres). Larger, more active people and anyone in hot weather need more; smaller, less active people may need less.
Do tea, milk and food count?
Yes, most drinks and water-rich foods like fruit, dal and curd add to your intake. Plain water is still the best main source.
How much more should I drink when exercising?
About 350–500 ml for every 30 minutes of exercise, more in heat or if you sweat a lot.
Sources
Last reviewed: October 2026