Water intake calculator
The numbers stay in this tab. Nothing is uploaded.
Water a day
35 ml per kg, plus 12 ml per minute of exercise, plus 500 ml in hot weather. A glass is 250 ml.
A rule of thumb for healthy adults, not medical advice. Food and other drinks count toward the total.
How to use this tool
Estimate how much water to drink a day from weight, exercise and climate. Nothing is uploaded.
Open Water intake calculator
70 kg, 30 minutes of exercise and a temperate climate are set. The total in litres and glasses sits on the right.
Enter your weight and exercise
Type the weight in kg or switch to lb. Enter the minutes of exercise on a typical day.
Set the climate
Pick Hot or humid to add half a litre. The breakdown shows how much comes from weight, exercise and climate. Copy puts it on the clipboard.
FAQ
How is daily water estimated?
About 35 ml per kilogram of body weight, plus about 12 ml per minute of exercise, plus 500 ml in hot or humid weather. A 70 kg person with 30 minutes of exercise gets about 2.8 litres.
Is anything uploaded?
No. The numbers stay in this tab.
Does the total include food and other drinks?
It is total fluid. Roughly a fifth usually comes from food, and tea, coffee and milk count toward it.
Is this a medical recommendation?
No. It is a rule of thumb for healthy adults. Pregnancy, breastfeeding, kidney or heart conditions and some medicines change the need; ask a doctor.
How big is a glass?
250 ml, about 8.5 US fluid ounces. The glass count is rounded up.