Water Intake Calculator
Estimate how much water to drink daily based on your weight and activity.
Enter your values to calculate your result.
Formula
Water (mL) = Weight (kg) x 33 mL + (Exercise Minutes / 30) x 350 mL
A commonly cited baseline is about 33 mL of water per kg of body weight per day, with an extra allowance for fluid lost to sweat during exercise (roughly 350 mL per 30 minutes of activity).
Example
A 70 kg person who exercises 30 minutes a day needs about 2.66 L of water daily (2.31 L baseline + 0.35 L for exercise).
Frequently Asked Questions
Does this include water from food and other drinks?
No — this estimates total water intake from all sources combined. In practice, food and other beverages contribute a meaningful share, so you may need less plain water than this number suggests.
Does climate affect this?
Yes, significantly — hot or humid climates increase fluid loss beyond what this baseline estimate accounts for.