Health & Fitness · Free tool
Daily Water Intake Calculator
Calculate how much water you should drink per day based on weight, activity, and climate. Liters and ounces.
Daily water target
2.8L
≈ 95 fl oz · 12 cups
Includes water from all drinks and food (food supplies roughly 20%). Add more in hot climates, when sick, or during long workouts.
What it does
A free daily water intake calculator that sizes your target based on weight and exercise — roughly 35ml per kg of body weight plus 355ml per 30 minutes of activity. Runs in your browser, no sign-up.
The “8 cups” rule is a starting guideline, not a prescription. Your real target depends on body mass, climate, activity level, and diet (water-rich foods reduce the plain-water requirement). Pair with our hydration guide for practical tactics to actually hit your number.
How to use it
- Enter your weight (metric or imperial).
- Add minutes of daily exercise.
- Read your daily water target in liters and ounces.
- Pair with a marked water bottle or bottle count to hit it.