Daily water by body weight
| Body weight | Approx. daily water |
|---|---|
| 50 kg (110 lb) | ~1.8 litres |
| 60 kg (132 lb) | ~2.1 litres |
| 70 kg (154 lb) | ~2.5 litres |
| 80 kg (176 lb) | ~2.8 litres |
| 90 kg (198 lb) | ~3.2 litres |
| 100 kg (220 lb) | ~3.5 litres |
Adjust for your day
Add roughly 10 ml per minute of exercise, and more in hot or humid weather. Illness, high altitude, and pregnancy or breastfeeding also raise your needs. The figures above are a baseline for a typical day.
The easiest hydration check
Forget counting to the millilitre — your urine colour tells you most of what you need to know. Pale straw means you are well hydrated; dark yellow means drink more. See how to drink more water for simple habits that help.