Water Intake Calculator
Estimate daily water needs based on body weight, activity, and climate. Outputs ounces, liters, cups, and glasses — these are guidelines, not strict rules.
Inputs
Daily water target
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Liters
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US cups (8 oz)
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8-oz glasses
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500 mL water bottles
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About Water Intake Calculator
How the estimate works
A common rule of thumb is roughly half to a full ounce per pound of body weight, plus extra for exercise. This calculator uses 0.6 oz/lb baseline plus 12 oz per 30 minutes of activity, scaled for climate.
Does food count?
About 20% of daily fluid comes from food — fruits, vegetables, soups. Coffee and tea count toward fluids despite mild diuretic effects; alcohol can be slightly dehydrating.
Signs of adequate hydration
Pale yellow urine. Most adults pee 4-7 times daily. Dark yellow or amber means drink more. Crystal clear all the time means you may be overdoing it.