Hydration Needs by Weight Calculator
Enter your body weight to get a general estimate of your daily recommended water intake.
Hydration Needs by Weight Calculator
Estimates a general daily water intake target based on your body weight.
This calculator applies a widely used rule-of-thumb — about 33 milliliters of water per kilogram of body weight per day — to give you a personalized general hydration target. It's a simple, weight-scaled starting point rather than a precise medical prescription, since actual fluid needs vary with activity level, climate, overall health, and diet. Use it as a baseline and adjust upward on hot days or during intense exercise.
Example
- With the default values shown above, this calculator returns: Recommended Daily Water Intake ≈ 2.31 liters.
Frequently Asked Questions
Where does this estimate come from?
It uses a commonly cited general guideline of roughly 33 ml of water per kilogram of body weight per day as a starting reference point.
Does this account for exercise or hot weather?
No — this is a baseline estimate; you'll typically need more fluids on days with heavy exercise, hot weather, illness, or other conditions that increase fluid loss.
Does this include water from food and other drinks?
This estimate is for total daily water/fluid intake broadly; if you want water from beverages specifically, you may adjust down slightly to account for water content in food.
Sources
- Standard formula, publicly documented method