water intake calculator
Daily hydration goal based on your weight, activity and climate. No sign-up.
Hydration facts
| WHO guideline | ~2 L/day women |
| WHO guideline | ~2.5 L/day men |
| 1 US cup | = 237 ml |
| 1 standard glass | = 250 ml |
| 1 litre | = ~4 glasses |
| Body is ~60% water | |
| Mild dehydration | 1–2% body weight |
| Severe dehydration | >5% body weight |
Signs of dehydration
Dark urine, headache, fatigue, dry mouth, dizziness and reduced concentration are early signs. Pale yellow urine is the target.
Tips
Drink a glass first thing in the morning. Keep a water bottle at your desk. Eat water-rich foods (cucumber, watermelon, soup). Set hourly reminders.
FAQ
Does coffee count?
Yes — coffee, tea and other beverages count toward total fluid intake, despite mild diuretic effects. Plain water remains optimal.
How is this calculated?
Base: 35 ml per kg body weight. Multiplied by activity and climate factors. Extra ml added for pregnancy/breastfeeding per medical guidelines.
Is my data stored?
No — everything runs in your browser.