Water Intake Calculator: The Complete Guide
Find out how much water you should drink each day. Enter your body weight and how much you exercise to get a personalised daily target in litres, fluid ounces, and cups.
Who the Water Intake Calculator is for
People wanting a personalised daily hydration target rather than the generic 'eight glasses'.
How to use the Water Intake Calculator
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
A common guideline is about 35 ml of water per kilogram of body weight, plus roughly 350 ml for every 30 minutes of exercise. The result is shown in litres, ounces, and cups.
Features
- Personalised daily target
- Litres, ounces, and cups
- Adjusts for exercise
- kg or lb
How much water do you really need?
Hydration needs depend on body size, activity, climate, and health — so a fixed 'eight glasses' rule fits no one exactly. Scaling intake to body weight and exercise gives a far more useful target. Remember that food and other drinks also contribute, and thirst plus pale-yellow urine are good real-world guides.