Total Body Water Calculator
Estimate total body water with the Watson equations and show liters plus percentage of body weight.
Enter or adjust the values above, then calculate.
Total Body Water: watson Formula Estimate
Estimate total body water with the Watson equations and show liters plus percentage of body weight.
Inputs this tool uses
- Age
- Sex used by the formula
- Height
- Weight
What you get
Watson total-body-water estimate.
How to use the Total Body Water Calculator
- Enter age, sex used by the formula, height and the other fields relevant to this calculation.
- Select any method, activity level or option shown on this page, then choose Calculate.
- Read the main result together with the supporting values, method, assumptions and limitations below before using the estimate.
How this calculation works
Total body water is estimated with the sex-specific Watson equations using age, height and body weight.
Example calculation
The sample values loaded into the calculator produce 33.3 L. This example exists to show how the output is structured; replace the sample values with your own inputs for your calculation.
Assumptions and limitations
- Anthropometric formulas are estimates and can differ from direct clinical measurements.
- Results are educational screening/reference values and do not diagnose health conditions.
Sources and review status
Source set last verified 2026-09-25. No clinician review is claimed unless a real named reviewer is displayed.
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