Daily Water Intake Calculator
Estimate how much water you should drink today from your body weight, activity level and hot weather.
| Morning (wake – 11:00) | 578 ml |
|---|---|
| Before lunch (11:00 – 14:00) | 347 ml |
| Afternoon (14:00 – 18:00) | 578 ml |
| Dinner time (18:00 – 20:00) | 347 ml |
| Evening (20:00 – 22:00) | 462 ml |
What is it
Your target daily fluid intake follows your body size first: about 30-35 ml per kilogram of weight. Sweat adds more — exercise, manual work and hot weather each push the number up a bit. This tool starts from weight, adds activity and heat, then splits the total across the day so you do not gulp it all at once.
Notes & fun facts
You do not need to chug eight glasses at noon. The body flushes itself fine when water arrives in small steady pours — a glass after waking, one between meals. The two classic mistakes: saving the quota for the evening, and trying to drink back yesterday’s hangover in one morning.
Origin & history
The modern baseline comes from the US Institute of Medicine’s 2005 Dietary Reference Intakes (about 3.7 L total fluid for men, 2.7 L for women), echoed by EFSA’s 2010 values. The simple 30-35 ml-per-kg rule is a popular back-of-envelope conversion of those reports.