Water intake calculator
How much water to drink a day for your body weight and how often you train, in litres, ounces and cups. Same rule the TrackAI app uses for your water goal.
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Drinking water a day
81fl oz
10 cups · 2.40 litres
- Per waking hour (16 h)
- 5.1 oz
- 500 ml / 16.9 oz bottles
- 4.8
Log a glass in one tap
TrackAI tracks water against this goal, sends water reminders and its AI coach can log water for you. Try it free for 3 days.
How the calculation works
- 1
Body weight. About 30 ml of drinking water per kg of body weight a day (roughly half an ounce per pound).
- 2
Training. 10% more if you work out 3 or more times a week.
- 3
Cap. The target stops at 3 litres (about 101 oz or 12 cups), the same cap the TrackAI app uses; food and other drinks cover the rest of your fluid.
Official guidelines for total water
| Source (adults, from all drinks and food) | Women | Men |
|---|---|---|
| US National Academies | 2.7 L | 3.7 L |
| European Food Safety Authority | 2.0 L | 2.5 L |
About 20% of total water usually comes from food, which is why the drinking target above is lower than these totals. Not medical advice: if you have heart or kidney disease or a doctor has limited your fluids, follow their advice. Working out your food too? Try the calorie calculator.
Questions
How much water should I drink a day?
A practical rule is about 30 ml per kg of body weight (half an ounce per pound), a little more if you exercise, which lands most adults between 2 and 3 litres of drinking water. The US National Academies put total water at about 2.7 litres a day for women and 3.7 litres for men, but that includes the roughly 20% that comes from food.
Do coffee, tea and other drinks count?
Yes. Coffee and tea count toward your fluid intake; the mild diuretic effect of caffeine does not cancel out the water in the cup for regular drinkers. Water is still the best default because it has no calories or sugar.
How much more water do I need when I exercise?
Roughly 400 to 800 ml per hour of exercise, more in heat or if you sweat heavily. This calculator adds 10% to your daily target if you train three or more times a week; on long or hot sessions, drink to thirst on top of that.
How many cups of water is that?
One US cup is 8 fluid ounces, or about 237 ml, so a litre is about 4.2 cups. The result shows your target in litres, ounces and cups.
Can you drink too much water?
Yes, though it is rare: drinking several litres in a short time, especially during long endurance events, can dilute blood sodium (hyponatremia). Spread water across the day and let thirst and pale-yellow urine guide you.