Water Intake Calculator
Calculate exactly how much water you should drink daily based on body weight, activity level, climate zone, and diet. Includes net hydration tracker and hourly reminder schedule. Free.
Frequently Asked Questions
How much water should I drink per day?+
The 8-glasses rule is outdated. Your needs depend on body weight, activity level, climate, and diet. A 70kg moderately active person in a temperate climate needs about 2.2L of drinking water (subtracting ~600ml from food).
Does coffee count towards daily water intake?+
Partially — coffee has a hydration coefficient of about 0.7, meaning 250ml of coffee contributes roughly 175ml of net hydration. It's not as dehydrating as commonly believed.
How does climate affect water needs?+
Hot, dry climates (like a desert) can increase your water needs by 800ml+ per day due to sweat and evaporation. Someone in Arizona needs significantly more water than someone in Canada in winter.