Daily water intake
A rough daily fluid target based on your weight, how much you moved, and the climate you are in.
Enter your weight to see an estimate.
Where the numbers come from
The baseline uses roughly 33 ml of fluid per kilogram of body weight, a commonly used rule of thumb for healthy adults. To that we add about 350 ml for every half hour of exercise, and an allowance for hot or humid conditions — which matters a great deal across most of India for much of the year.
“Eight glasses a day” is not a rule
It is a memorable phrase with no strong evidence behind it. Fluid needs vary enormously with body size, activity, temperature and health. Roughly a fifth of most people's water intake also comes from food — fruit, vegetables, dal, curd and soups all count, as do tea, coffee and milk.
A better signal than any calculator
Look at your urine. Pale straw generally means you are adequately hydrated; consistently dark yellow suggests you need more. Thirst is a reasonable guide for most healthy adults, though it becomes less reliable with age.
When this calculator does not apply
Do not use it if you have heart failure, kidney disease, liver disease, or any condition for which a doctor has told you to restrict fluid — in those situations drinking to a generic target can be actively harmful. Drinking very large volumes very quickly can also dangerously dilute blood sodium. Follow the advice you have been given in person.