Water Intake Calculator
Calculate how much water you should drink per day from your body weight and activity level — free online. — free, fast and private.
How to use Water Intake Calculator
- Enter your body weight in kilograms.
- Choose your activity level for the day.
- Click Calculate Water Intake to see your daily target in litres and glasses.
Note: this tool runs in your browser. Nothing is uploaded.
Disclaimer: this tool gives an estimate for general information only. It is not medical advice. Talk to a doctor or other qualified health professional before making any health decision.
Frequently Asked Questions
How much water should I drink per day?
A common guide is about 35 ml per kilogram of body weight — roughly 2.5 litres for a 70 kg adult — plus more when you exercise or in hot weather. Thirst, urine colour and your doctor's advice are better guides than any fixed number.
Is this tool free to use?
Yes, it is 100% free with no sign-up. Your data stays in your browser.
Is my data uploaded or stored?
No. This tool runs entirely in your browser — nothing you enter is uploaded to a server.
Can I use it on my phone?
Yes, it is fully mobile-friendly and works in any modern browser on phone, tablet or computer.