Water Intake
Water intake calculator
A common guideline is about 35 ml of water per kg of body weight, plus roughly 350 ml per 30 minutes of exercise. A 70 kg person is around 2.5 L a day at rest, more when active. Enter your details below — climate, thirst, and diet also matter.
—
Millilitres
—
US fluid ounces
—
Cups (8 oz)
—
Frequently asked questions
How much water should I drink a day?
~35 ml/kg body weight + ~350 ml per 30 min exercise. A 70 kg person ≈ 2.5 L at rest, more when active. Thirst and climate matter too.
Does "8 glasses" apply to everyone?
It's a rough average. Bigger/more active people need more; some water comes from food. Scaling to weight and activity is better.
Can I drink too much?
Rarely, but yes — very large amounts fast can dilute sodium. Spread intake and drink to thirst.
A general estimate, not medical advice. Needs vary with health, climate, and activity — drink to thirst.