About 33ml per kilogram of body weight
That is a common rule of thumb — a 60kg person lands around 2 liters a day. On top of that base, this calculator adds more for a physically demanding routine, hot weather, or exercise, since all three push up how much you lose through sweat.
Food counts too
Daily water needs include the water already in your food — soup, fruit, and vegetables all carry a lot of it. If you eat a normal, varied diet, you do not need to drink the entire recommended amount as plain water.
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Frequently asked questions
QIs drinking more always better?
No. Drinking a very large amount in a short time can dilute sodium in the blood (hyponatremia), which is rare but dangerous. Spreading intake across the day is safer than drinking it all at once.
QWhat is the most reliable signal?
For a healthy adult, thirst plus pale yellow urine is a good enough guide. If you have a heart or kidney condition, or take diuretics, follow your doctor's fluid guidance instead of a general calculator.
QDoes coffee or tea count toward the total?
Caffeinated drinks still contribute fluid overall, though the old idea that caffeine causes net dehydration is largely outdated for regular drinkers. Plain water is still the simplest way to hit the number.