Your body weight is the single best starting point for estimating how much water you need each day. Use this daily water intake by weight calculator to get a personalized baseline in seconds.
Water Intake by Weight
Rule of thumb: about 35 ml of water per kilogram of body weight.
For information only — not medical advice.
Why weight is the best starting point
Larger bodies have more cells, more blood volume, and a faster metabolism — all of which need more water. That is why generic advice like “drink 8 glasses a day” undershoots for some people and overshoots for others. Scaling intake to your weight gives you a target that actually fits your body.
Quick reference
- 50 kg (110 lbs) → 1.75 L (about 7 glasses)
- 60 kg (132 lbs) → 2.10 L (about 9 glasses)
- 70 kg (154 lbs) → 2.45 L (about 10 glasses)
- 80 kg (176 lbs) → 2.80 L (about 12 glasses)
- 90 kg (198 lbs) → 3.15 L (about 13 glasses)
Fine-tune your number
This is your baseline. Drink more if you exercise, sweat heavily, live in a hot climate, are pregnant or breastfeeding, or are fighting off an illness. Try our full water intake calculator for a target that includes activity and climate.
For information only — not medical advice.