How much water should I drink a day?

A common starting guideline is about half to one ounce of water per pound of body weight per day, adjusted upward for exercise, heat, and activity level. This calculator uses a weight-and-activity-based estimate as a starting point.

Does this water intake target include water from food?

This estimate reflects total fluid intake, not just plain water. In practice, food (especially fruits and vegetables) and other beverages contribute a meaningful share of daily hydration alongside water itself.

Water intake calculator

Estimate a daily hydration target based on your body weight and how active you are.

Weight (lbs)

Activity level

Ounces/day

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Cups/day

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Liters/day

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This is a starting target, not a hard rule — thirst, urine color, climate, and how much you sweat during exercise all matter too.

How this is calculated

We multiply your body weight in pounds by a factor between 0.5 and 0.8 depending on activity level — based on the commonly cited guideline of roughly half to one ounce of water per pound of body weight per day, scaled up for higher activity.

Individual fluid needs vary with climate, health conditions, and medications. Talk to a healthcare provider if you have kidney, heart, or other conditions that affect fluid intake.

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