An estimate of how much water you need each day based on your weight, exercise and the heat.
How it works
A practical rule is about 35 ml per kilo of body weight, plus half a litre for every 40 minutes of exercise and a bit extra in hot weather. EFSA (the European Food Safety Authority) recommends a total intake of 2 litres a day for women and 2.5 for men, including water from food.
Around 20% of your water comes from food, so what you drink can be a little less.
Frequently asked questions
Do coffee and tea count?
Yes, they count as fluid. Caffeine’s mild diuretic effect doesn’t cancel out what they provide.
More health and fitness calculators
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Body fat — Body fat percentage with a tape measure (US Navy method).