Water Intake Calculator
Enter your weight and how long you exercise each day to get a daily water target in litres, 250 ml glasses and US fluid ounces.
Water Intake
How much water to drink per day
Water per day2.7 L
Glasses (250 ml)11
US fluid ounces90
How it works
- Baseline: about 33 ml per kg of body weight.
- Add roughly 350 ml for every 30 minutes of exercise.
- Hot weather, illness and breastfeeding increase needs.
- Food and other drinks also count toward your fluid intake.
Worked example: 70 kg, 30 minutes of exercise
- 170 × 0.033 = 2.31 L.
- 2Exercise: + 0.35 L.
- 3Total ≈ 2.7 L.
≈ 2.7 litres — about 11 glasses
Daily water by body weight (no exercise)
| Weight | Litres | Glasses |
|---|---|---|
| 50 kg | 1.7 | 7 |
| 60 kg | 2.0 | 8 |
| 70 kg | 2.3 | 9 |
| 80 kg | 2.6 | 11 |
| 90 kg | 3.0 | 12 |
Frequently asked questions
Do I really need 8 glasses a day?
It is a rough rule. Needs depend on body size, activity and climate.
Does coffee count?
Yes, coffee and tea contribute to fluid intake in moderate amounts.
Can I drink too much water?
Yes, very large amounts in a short time can be dangerous. Spread intake through the day.
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