Water Intake Calculator
Enter your weight, activity level and climate to get a realistic daily water goal — shown in liters, cups and standard bottles so it's actually actionable.
Frequently asked questions
How much water should I drink per day?
A common baseline is about 30–35 ml per kilogram of body weight (roughly 0.5 oz per pound) — about 2.1–2.5 liters for a 70 kg adult. Exercise, heat and pregnancy all increase needs. The “8 glasses a day” rule is a decent rough target but ignores body size: a 50 kg and a 110 kg person have very different needs.
Does coffee count toward my water intake?
Yes. Despite the popular belief that caffeine dehydrates you, research shows the fluid in coffee, tea and other drinks contributes to daily hydration. Food also provides water — fruit, vegetables and soup can account for around 20% of total intake. Plain water remains the best default because it adds nothing else.
Can I drink too much water?
Yes, though it’s rare. Drinking several liters in a short time can dilute blood sodium (hyponatremia), which is dangerous. It’s most often seen in endurance athletes drinking far more than they sweat. Spread your intake across the day and drink to thirst plus activity, not by force.