Water Intake Calculator
Estimate how much water you should drink each day based on your body weight, activity level, and climate.
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Reviewed
July 2026
How This Is Calculated
Daily water needs depend on body size, how active you are, and the climate you’re in. This calculator gives a practical starting estimate rather than a strict medical requirement.
The Formula
Baseline = weight(kg) × 33 ml. We then add extra liters for activity level and hot/humid climates.
Adjusting Day to Day
Thirst, urine color, and exercise intensity are all useful day-to-day signals. Treat this number as a baseline to adjust around, not a fixed rule.
A starting point, not a strict requirement.
Individual needs vary with health conditions, medications, and diet. Consult a healthcare provider for specific medical guidance.
Sources
Frequently asked questions
How much water should I really drink daily?
General guidelines suggest roughly 30–35ml per kg of body weight, adjusted upward for hot climates, higher activity levels, or increased sweat loss.
Do other drinks and food count toward hydration?
Yes — food and other beverages contribute meaningfully to total fluid intake, so this estimate is a helpful target rather than a requirement for plain water alone.
Can I drink too much water?
It's possible, though uncommon, to overhydrate to the point of diluting sodium levels — this mainly happens with very large, rapid intakes rather than steady daily hydration.
Does exercise change how much water I need?
Yes — sweat losses during exercise increase your fluid needs, which is why activity level is factored into this estimate.