Enter your weight and workout time to see how many litres of fluid are recommended a day.
The calculator is a guide, not medical advice. If you have a health condition or are pregnant, talk to a doctor or dietitian.
The base need is about 33 ml per kg of body weight. About 12 ml is added for every minute of exercise (roughly 0.7 l an hour) because you lose fluid in sweat. Adults get about a fifth of their fluids from food.
The European Food Safety Authority puts total water intake from drinks and food at about 2 l for women and 2.5 l for men. Your exact need depends on weight, heat and activity.
Yes, all drinks count towards your fluids, though water is best because it has no sugar or calories.
Dark yellow urine, a dry mouth, headache and tiredness often point to too little fluid. Pale yellow urine suggests you have enough.
It is rare in healthy people, but drinking a very large amount in a short time can lower blood sodium. Drink steadily through the day.