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Daily Water Intake & Insensible Loss Calculator

Estimate your daily water requirement and insensible loss (water lost through evaporation) from your weight and age group. See instantly how many cups that is — a free tool to help set your hydration target.

This tool gives a rough estimate based on common formulas. Your actual needs change with fever, exercise, or medical conditions. Always consult a doctor for health decisions.

Input

kg
Age group

Result

Daily water requirement

2,100mL/day

About 2.1 L (weight × 35 mL/kg/day)

Cups (200 mL) equivalent

About 11 cups

Insensible loss (evaporation)

900 mL/day

Per-weight factor

35 mL/kg/day

How it works

  • Daily water requirement is estimated as "weight (kg) × an age-group factor (mL/kg/day)". The factor is about 60 mL/kg for children, 35 mL/kg for adults, and 25 mL/kg for the elderly (adult value based on a 30–35 mL/kg/day guide).
  • Insensible loss is estimated as "weight (kg) × about 15 mL/kg/day". It rises with sweating and fever.
  • The cup figure is calculated at 200 mL per cup.
  • The requirement is a guide for total intake from drinks, food, and metabolic water combined — you do not need to get it all from beverages.
  • Needs increase with fever, exercise, and hot environments, while heart or kidney disease may require fluid restriction; individual variation is large.
  • This tool provides a rough estimate based on common formulas and is not a diagnosis or medical advice. Always consult a doctor for health decisions.