Total Body Water Calculator
Total body water is most of the lean tissue. The Watson equation estimates litres from age, height, weight and sex.
Result
Enter the values and press Calculate. Numbers outside the allowed range produce no result.
How is it calculated?
In adults, body water is roughly 50–65% of weight. Men usually sit higher because of more muscle.
Men: 2.447 − 0.09156×age + 0.1074×cm + 0.3362×kg Women: −2.097 + 0.1069×cm + 0.2466×kg
Reference table
| Group | Rough share |
|---|---|
| Adult men | %55–65 |
| Adult women | %45–60 |
How should you read the result?
Edema, dialysis, pregnancy and severe dehydration break the estimate. This page does not tell you how much to drink.
Frequently asked questions
What body water percentage is normal?
About 50–65% is common in healthy adults. There is no single ideal number.
Does drinking raise the percentage immediately?
A drink raises both weight and water briefly. The equation is not a real-time measure.
Does it detect dehydration?
No. It is an anthropometric estimate, not a urine or blood test.
Why is age missing for women?
Watson's female equation uses height and weight; the male equation also includes age. That is the original regression.