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Use this calculator to estimate daily water intake based on body weight and activity level. It can help with general hydration planning and day-to-day wellness awareness.
This page gives a practical estimate only. Individual hydration needs may differ based on health condition, environment and personal routine.
A water intake calculator estimates how much water a person may need each day based on body weight and physical activity level. It is useful for general hydration awareness and daily routine planning.
Water plays an important role in temperature regulation, digestion, circulation and overall body function, so many people like to use a rough estimate as a starting point.
The estimate increases with higher activity because active people may lose more fluid through sweat.
Estimated Daily Water (ml) = Body Weight (kg) × 35 × Activity Factor
This is a simple planning formula designed for everyday use rather than clinical hydration assessment.
Suppose a person weighs 70 kg and has a moderately active lifestyle with an activity factor of 1.4.
Estimated daily water = 70 × 35 × 1.4 = 3430 ml
That is about 3.43 liters per day, or roughly 14 glasses of 250 ml each.
This calculator gives a general hydration estimate. Actual water needs may vary because of weather, sweating, diet, caffeine intake, illness, pregnancy, medical conditions, medication use and age.
If someone has a health condition or specific hydration concerns, personalized medical guidance is more appropriate than a general estimate.
Disclaimer: This calculator is provided for informational and general wellness purposes only. It is not a medical diagnosis or treatment tool.