Water Intake Calculator
Estimate how much water you should drink per day based on your weight and activity.
Result
Daily water (litres)
2.66
Glasses (250 ml)
11
How it works
A common rule of thumb puts daily fluid needs near 30–35 ml per kilogram of body weight, so a 70 kg adult lands around 2.1–2.5 litres. Activity, heat and altitude push it higher, and this calculator adds an allowance for how much you move. That total is all fluid, not just plain water. Tea, coffee, milk, soup and juice all count, and food contributes a surprising amount — fruit and vegetables are mostly water, and a typical diet supplies perhaps a fifth of your intake before you drink anything. Healthy kidneys handle a wide range, which is why rigid targets matter less than they seem. Thirst is a reliable guide for most people, and the practical check is colour: pale straw means you are well hydrated, dark yellow means drink more. Some conditions and medications change these needs, so follow medical advice over any formula.
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Frequently asked questions
How much water should I drink per day?
A common guideline is about 30–35 ml per kg of body weight, adjusted for activity and climate. This calculator estimates it from your weight.
Do coffee and tea count toward my water intake?
Yes, most beverages contribute to hydration, but plain water is best. Increase your intake during exercise, hot weather, or illness.
How do I know if I am drinking enough?
Check urine colour. Pale straw suggests good hydration; dark yellow or amber means drink more. Very frequent, completely clear urine can mean you are overdoing it.
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