About this water intake calculator
Hydration needs vary. A common rule of thumb is about 33 ml per kg of body weight, with extras for exercise and heat. Medical conditions can change requirements.
How to use
- Enter weight in kg.
- Add activity and climate extras if needed.
Formula
Liters ≈ (weight_kg × 33) / 1000 + extras
Worked examples
Example: 70 kg baseline ≈ 2.31 L/day before activity extras.
Tips
- Thirst, urine color, and climate matter more than any single formula.
Frequently asked questions
How much water should I drink a day?
Many adults land near 2–3 liters from drinks plus food moisture, but needs vary. Use this as a starting estimate.