Daily Water Intake Calculator
Enter your weight, age, and lifestyle to get a personalized daily hydration target — down to the exact millilitre. You'll also get a drinking schedule so you can spread your intake throughout the day rather than trying to catch up in the evening.
Fill in your details on the left and we'll calculate exactly how much water you need today — and every day.
What's factored in:
while awake (based on 16 waking hours)
Suggested daily drinking schedule
Tips to hit your target
Why your exact number matters
Generic advice says "8 glasses a day" — but that ignores body size entirely. A 50 kg woman and a 100 kg man have very different fluid needs. The weight-based formula (≈33 ml per kg) is what most clinical guidelines use as a starting point, adjusted for age, sex, activity, and environment.
About 20% of daily fluid intake comes from food (fruits, vegetables, soups). This calculator gives you a pure drinking target — the water you should consume as liquid, separately from meals.
Recognise dehydration before it hits hard
Thirst is a late signal — by the time you feel thirsty, you're often already 1–2% dehydrated, enough to impair concentration and physical performance. Watch for earlier cues: