Water Intake Calculator — Daily Water Needs
Estimate how much water to drink a day from your weight, exercise and climate — in litres, ounces and cups. A general guide, in your browser.
🔒 Calculated in your browser. A general guideline (~33 ml/kg + exercise + climate) — not medical advice. Needs vary; some conditions require different intake.
How much water a day
Enter your weight and, optionally, your daily exercise minutes and whether you’re in a hot climate. The tool estimates a daily target using a common guideline (about 33 ml per kg, plus ~350 ml per 30 minutes of exercise, plus a hot-climate allowance) and shows it in litres, ounces and cups.
A guide, not a rule
Hydration needs vary with activity, health, pregnancy and diet, and food and other drinks count too. Use this as a starting point, not a strict quota, and follow medical advice for any condition that affects fluid intake. Everything runs in your browser.
Frequently asked questions
How much water should I drink a day?
A common guideline is ~33 ml per kg of body weight, more with exercise and heat. For a 70 kg person that’s about 2.3 litres — but needs vary.
Does coffee or food count?
Yes — food and other drinks contribute to hydration. This tool estimates total water; you don’t need to drink it all as plain water.