Free calculator
Water Intake Calculator
A quick, practical estimate: about 35 ml per kilogram, plus extra for exercise and hot, humid weather.
How it works
Baseline 35 ml × kg, plus 12 ml per minute of exercise, plus 0 / 250 / 500 ml for cool / mild / hot climates. About 20% of your water also comes from food. Glasses are 250 ml.
People with kidney, heart or liver conditions, or who take diuretics, may be on a fluid limit. Follow your doctor’s advice.
Frequently asked questions
Does tea or coffee count?
Yes, mostly. So do soups, buttermilk, coconut water and water-rich fruit.
How do I know I am drinking enough?
Pale yellow urine and rarely feeling thirsty are good signs.
Can I drink too much?
Rarely, but several litres in a short time can dilute blood sodium. Spread intake through the day.
General estimates for information only. Not medical or professional advice. Nothing you enter is saved or sent to us.