Daily Water Intake Calculator
Use the calculator to create a practical drinking-water estimate based on your body weight, usual activity and climate.
Open the calculatorCalculation method
Base estimate: body weight in kg × 35 ml. A 70 kg adult begins at 2,450 ml. The calculator adds 0, 250, 500 or 750 ml for the selected activity level, and 0, 400 or 700 ml for normal, hot or very hot conditions.
This is a practical educational estimate of drinking water, not a diagnosis or a target for total daily fluids. Food and other drinks can add to fluid intake.
Medical note: Ask a qualified healthcare professional for personal guidance if you are pregnant, breastfeeding, have kidney or heart disease, fluid restrictions, diabetes, or take medicines that affect hydration.