Water intake calculator
Hydration needs vary with body size, activity and climate. This gives a reasonable daily water target as a starting point.
Fill in the fields above and press Calculate.
How it’s calculated: Water (ml) = weight (kg) × 33 + activity allowance. Estimates for educational use — not medical advice.
Frequently asked questions
- How much water should I drink a day?
- A common guideline is about 30–35 ml per kg of body weight, adjusted up for exercise and hot weather. Thirst and pale-yellow urine are good day-to-day signals.
- Does coffee or tea count?
- Yes — the fluid in most drinks and water-rich foods counts toward your daily total. The mild diuretic effect of caffeine is small.
- Can you drink too much water?
- Rarely, but drinking extreme amounts very quickly can dilute blood sodium (hyponatremia). Spread intake through the day.