Does this include water from food and other drinks?

This estimate focuses on fluid intake generally; food and other beverages also contribute to total hydration.

Do I need more water in hot weather or at altitude?

Yes, heat, humidity, altitude and intense exercise increase fluid loss, so choose a higher activity level in these conditions.

Is this medical advice?

No, follow your doctor's specific guidance if you have a condition that affects fluid intake.

Water Intake Calculator

Estimate how much water you should drink each day

Body Weight

Activity Level

What is the Water Intake Calculator?

This calculator gives a general estimate of how much water to drink daily, based on your body weight and activity level. It's a simplified guide, not a precise physiological requirement — actual needs vary with climate, health conditions, diet and individual differences.

How to Use the Water Intake Calculator

Enter your body weight in kg or lb.
Choose your activity level.
Read your estimated daily water intake in liters, ounces and cups.

How It's Calculated

Daily Water (L) = Weight (kg) × 0.033 × Activity Multiplier

This baseline of about 33 mL per kilogram of body weight is a commonly cited general guideline, scaled up for more active lifestyles or hot climates. It covers water from drinks generally — food and other beverages also contribute to total hydration.

Frequently Asked Questions

This estimate focuses on water/fluid intake generally. Food (especially fruits and vegetables) and other beverages also contribute meaningfully to your total daily hydration.

Yes — heat, humidity, altitude and intense exercise all increase fluid loss through sweat and breathing. Choose "Active" for a higher estimate in these conditions.

No. If you have a kidney, heart or other condition that affects fluid intake, follow your doctor's specific guidance rather than a general calculator.