Water Intake Calculator
Find out how much water you should drink per day based on your body weight and activity. Instant hydration target in liters and glasses.
About this tool
This water intake calculator gives you a daily hydration target based on your body weight and exercise minutes. The baseline rule is about 33 ml per kilogram of body weight, plus roughly 35 ml per 30 minutes of physical activity.
Consistent hydration supports focus, energy, digestion and physical performance — and hitting the target with plain water is one of the cheapest health upgrades available. Use the cups and glasses conversions to make the habit easy to track.
FAQ
How much water should I drink?
A common guideline is 30–35 ml per kg of body weight per day, so a 70 kg adult needs about 2.3–2.5 liters. Exercise, heat and diet raise the need.
Does coffee and tea count?
Yes, mostly. Caffeinated drinks have a mild diuretic effect but still contribute to your daily fluid total.
What are signs of dehydration?
Dark urine, thirst, headache, fatigue and dizziness. Thirst itself means you are already slightly behind.