About this water intake calculator
Get a general daily water intake target based on your body weight and activity level. Enter your weight and choose sedentary, moderate, or active, and see a suggested daily total in liters and in 250 milliliter glasses. This uses a commonly cited baseline of about 35 milliliters per kilogram of body weight, scaled up slightly for more active days, as a simple starting point rather than a precise medical prescription, since actual needs vary with climate, health conditions, and diet.
How it works
Baseline intake is 35 mL multiplied by your body weight in kilograms. That baseline is then scaled by 1.0 for sedentary, 1.1 for moderate, or 1.2 for active, and converted to liters and to a count of 250 mL glasses.
Try these examples
70 kg, moderate activity
2.70 liters · about 10.8 glasses
60 kg, sedentary
2.10 liters · about 8.4 glasses
Limitations & privacy
This is a general estimate, not medical advice. It does not account for climate, pregnancy, breastfeeding, illness, or medical conditions that change fluid needs. People with kidney, heart, or liver conditions should follow a clinician's specific guidance instead.
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A few good questions
Does this count water from food and other drinks?
No, this estimates total water-equivalent intake as a target; roughly a fifth of daily fluid typically comes from food, so plain drinking water needs may be somewhat lower in practice.
Why does activity level matter?
More physical activity increases fluid loss through sweat, so the multiplier raises the daily target for moderate and active lifestyles.
Is more water always better?
No. Drinking far beyond your body's needs can dilute blood sodium levels. This estimate is a reasonable target, not a floor to exceed aggressively.
Updated September 19, 2026