How much water should I drink per day?

A common guideline is about 2–3 liters (8–12 cups) per day, but the right amount depends on your body weight, activity level, climate, and lifestyle factors. This calculator provides a personalized estimate.

Does coffee count toward my water intake?

Coffee and tea do contribute to hydration, but caffeine has a mild diuretic effect. This calculator adds a small adjustment when you select the caffeine lifestyle factor to compensate for increased fluid loss.

Should I drink more water when exercising?

Yes. Physical activity increases fluid loss through sweat. The calculator accounts for this via the activity level selector. For intense or prolonged exercise, consider drinking an additional 0.5–1 liter per hour of activity.

Can I drink too much water?

Yes, overhydration (hyponatremia) can be dangerous, though it is rare. It typically occurs only during extreme endurance events. For most people, drinking to thirst and following recommended guidelines is safe.

How does climate affect water needs?

Hot and humid environments increase sweating and fluid loss, raising your daily needs. Cold climates can also increase fluid loss through respiration. The calculator adjusts your target based on your selected climate.

Is the 8-glasses-a-day rule accurate?

The "8 glasses a day" rule is a simplified guideline. Actual needs vary based on body size, activity, diet, and environment. A weight-based calculation like this one provides a more personalized recommendation.

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Water Intake Calculator

Get personalized hydration goals based on your body, activity, and lifestyle.

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