Fitness & Health

Total Body Water Calculator (Watson Formula)

Estimates your total body water with the Watson formula from age, sex, height, and weight. It reports TBW in liters, as a percent of body weight, and alongside a Hume-Weyers comparison.

How to use
  1. Enter your age and sex.
  2. Enter your height and weight.
  3. Check the percent of body weight and the Hume-Weyers value.
Estimates for general wellness, not medical advice. Check with a doctor or dietitian before acting on health figures.
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Common questions

What percent of the body is water?

It's commonly around 50 to 60 percent of body weight, higher in men and lower with more body fat. The Watson formula estimates your figure from age, sex, height, and weight.

Why compare Watson and Hume-Weyers?

They're two validated equations that can differ slightly. Showing both gives you a sense of the estimate's range.

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