Insulated 500 ml bottle
Everyday size that matches one “bottle” in the calculator result.
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Water Intake Calculator
Estimate how much water to drink each day from your weight, activity, and climate. Get a clear daily target plus glasses and bottles — in seconds.
Typical adult range. Switch kg/lb above.
Output unit
—
ml / day
—glasses (250 ml)
—bottles (500 ml)
Not medical advice. This is a general estimate for healthy adults. Needs vary with illness, pregnancy, medications, and individual health. Ask a clinician if you have fluid restrictions or medical conditions.
FAQ
How does this water calculator work?
We start from a commonly cited base of about 33 ml of water per kg of body weight, then apply activity and climate multipliers. Results update instantly in your browser — nothing is sent to a server.
Is 8 glasses a day enough?
“Eight glasses” is a rough rule of thumb. Your needs scale with body size, sweat loss, and heat. Use the calculator for a personalized starting point, then adjust how you feel.
Does coffee or tea count?
Most fluid from drinks counts toward hydration for healthy adults. Plain water is still the simplest default. Food moisture (fruit, soup) also contributes.
Should I drink more when I exercise?
Yes — pick a higher activity level. Long or hot sessions may need extra fluid beyond the daily target. Weigh yourself before/after hard workouts if you want a sweat-rate check.
Can I drink too much water?
Rare, but possible (hyponatremia). Don’t force extreme volumes. If you have kidney, heart, or endocrine conditions — or fluid limits from a doctor — follow clinical guidance instead of this tool.
kg or lb? ml, liters, fl oz, or cups?
Toggle weight between kg and lb, and output between ml, L, US fl oz, and 240 ml cups. The underlying math stays in milliliters.
Recommended bottles
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1 L marked bottle
Easy tracking toward a multi-liter daily target.
View placeholderGlass tumbler set (250 ml)
Matches the “glasses” count shown with your result.
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