Estimated Body Fat Calculator
A tape-measure estimate using the historical U.S. Navy circumference equations, for adults aged 18–65.
Your estimate
Complete the fields to see an estimate.
Rounded to a whole percentage point; this is not a direct fat measurement or health diagnosis.
All calculations run in your browser only — your data is never sent to a server or stored.
Which method is used?
We use the historical direct logarithmic Hodgdon–Beckett circumference variant reproduced in AR 600–9 (2019). Equations and waist sites differ by sex parameter. Every measurement is converted from cm to inches by dividing by 2.54, without military half-inch rounding. This is not current military compliance guidance.
How can I take consistent measurements?
Use a flexible, non-stretch tape against skin without compressing it. Repeat two or three times and use a consistent average. Measure height without shoes and follow each field’s instructions; the female natural-waist site differs from the male abdomen site.
Is the estimate accurate for everyone?
The equations were developed in adult military populations; accuracy varies with age, body shape and population. Ages 18–65 define this tool’s scope, not validation in every adult. Do not use during pregnancy, fluid retention or conditions affecting circumferences. It is not equivalent to DEXA and does not diagnose cardiovascular health. Even consistent measurements may miss true fat changes.
Source and methodology
AR 600–9 (2019), Appendix B, Table B-5Other Useful Tools
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