Water Intake Calculator
Estimate your daily water intake from body weight and exercise. See your target in litres, millilitres, and ounces. Free and instant.
Independently verified for accuracy
Calculator by Toolsloft ↗- Daily water target
- 2.8 litres
- In millilitres
- 2800 ml
- In fluid ounces
- 94.68 oz
Estimate how much water to drink in a day from your body weight and how long you exercise. It gives a daily target in litres, millilitres, and fluid ounces so you can set a bottle goal.
How this is calculated
The baseline is 35 millilitres of water per kilogram of body weight, a common clinical rule of thumb, plus 350 millilitres for every 30 minutes of exercise to cover sweat loss. Pounds are converted to kilograms at 0.45359237. This is a general guide, not medical advice, and needs rise in heat, illness, and pregnancy.
How to use
- Enter your body weight and choose kilograms or pounds.
- Enter how many minutes of exercise you do on the day.
- Read your estimated daily water target.
Examples
- 70 kg, 30 min exercise:
2.8 litres (94.68 oz) - 160 lb, no exercise:
2.54 litres (85.89 oz)
FAQ
- How is the water target calculated?
- It starts from 35 millilitres per kilogram of body weight, a widely used estimate for healthy adults, then adds 350 millilitres for each 30 minutes of exercise. Food also provides water, so treat the number as a drinking target rather than a strict limit.
- Does coffee or tea count toward the total?
- Mostly yes. Despite their reputation, moderate amounts of coffee and tea contribute to daily fluids for most people. Plain water is still the easiest way to hit the target without added sugar or calories.
- When do I need more than this estimate?
- Hot or humid weather, fever, vomiting, diarrhoea, high altitude, and pregnancy or breastfeeding all raise your needs. Use the figure as a starting point and drink more when you are sweating heavily or feel thirsty.