Water Intake Calculator
How much water should I drink? Daily target in liters, ml and cups.
Reviewed by the WorldCalcs team · Methodology · Last reviewed: June 2026
Daily water target
2.45 L
About 2 450 ml — roughly 10.3 cups (1 cup = 237 ml).
This is a general estimate, not medical advice. Real needs vary with climate, diet, health and activity. See our Disclaimer.
What is a water intake calculator?
A water intake calculator estimates how much water you should drink in a day, based on your body weight and how much you exercise. It is a helpful starting point rather than a strict rule: your real needs change with the weather, your diet (food provides water too), pregnancy, illness and how active you are. Use it as a daily target and adjust by listening to your body.
How it's calculated
A common rule of thumb is about 35 ml of water per kilogram of body weight, plus roughly 350 ml extra for every 30 minutes of exercise to replace what you lose through sweat. If you enter your weight in pounds, it is converted to kilograms first. The result is shown in liters, milliliters and cups so you can track it whichever way you prefer.
Example
A person weighing 70 kg with no exercise has a target of about 70 × 35 = 2,450 ml, or 2.45 liters (around 10 cups). Adding 30 minutes of exercise raises it to about 2,800 ml.
Pair this with our Calorie Calculator and BMR Calculator to round out your daily plan.
All calculations happen in your browser. Nothing is sent, stored, or tracked.
Results are estimates and may contain errors — for general information only, not professional advice. Always verify before relying on them. Disclaimer
How to use
Pick metric or imperial, enter your weight, and add the minutes of exercise you do per day. The result updates instantly in liters, milliliters and cups.
This is a daily target — adjust based on climate, diet and how thirsty you feel.
Frequently asked questions
How much water should I drink a day?+
Does water from food count?+
Do I need more water when exercising?+
Do coffee and tea count toward water intake?+
Is the "8 glasses a day" rule correct?+
Can you drink too much water?+
Does body weight affect how much water I need?+
How do I know if I am drinking enough?+
References
- General hydration guidance — approximately 35 ml of water per kg of body weight per day is a widely used rule of thumb; total water needs also include water from food.