Water Intake Calculator
Calculates your recommended daily water intake based on your body weight, activity level, and climate. Results include litres, millilitres, 8 oz glasses, 500 ml bottles, and US fluid ounces.
| Activity | Added fluid |
|---|---|
| Sedentary | — |
| Lightly active | +350 ml |
| Moderately active | +700 ml |
| Very active | +1050 ml |
| Athlete / hard training | +1400 ml |
The 35 ml/kg baseline is the most widely cited clinical recommendation for adults at rest in a temperate climate. About 20% of daily fluid needs typically come from food (fruits, vegetables, soups).
The standard recommendation is 35 ml of water per kilogram of body weight per day. This covers basic bodily functions at rest in a temperate climate.
Exercise increases fluid loss through sweat. Add approximately 350–500 ml per hour of moderate exercise, more for intense or prolonged sessions.
Hot or humid environments accelerate fluid loss through sweat and respiration. Add 500–1000 ml on very hot days.
About 20% of your water intake comes from food (fruits, vegetables, soups). The recommendation shown is for beverage intake only.
- •Drink a large glass of water first thing in the morning — you lose water overnight through breathing.
- •Dark urine = dehydrated. Pale yellow = well hydrated. Clear = possibly over-hydrated.
- •Coffee and tea count toward intake, despite the mild diuretic effect of caffeine.
- •Thirst is a lagging indicator — don't wait until you're thirsty to drink.