Body Fat Calculator — How to Estimate Body Fat Percentage
Estimate body fat percentage with U.S. Navy circumference formulas (Army option on the same page). Example: male 178 cm height, neck 40 cm, waist 86 cm → about 15.3%. Runs in your browser; educational only — not medical advice or a diagnosis.
How it works
Enter sex, height, and tape measurements in centimetres. The tool converts to inches for the published log10 circumference formulas, then shows estimated body fat %. Skinfold stays in FAQ — same page.
Formula and measurement assumptions
Male: %BF ≈ 86.010×log10(waist−neck) − 70.041×log10(height) + 36.387 (inches). Female: %BF ≈ 163.205×log10(waist+hip−neck) − 97.684×log10(height) + 78.387. Assumptions:
- Tape at standard Navy/DoD points; posture and clothing change results.
- Inputs are centimetres converted with 1 in = 2.54 cm before the log10 formulas.
- Estimates are educational illustrations, not DXA/Bod Pod clinical results or medical advice.
Example
Example: male, Navy method, height 178 cm, neck 40 cm, waist 86 cm → about 15.3% body fat.
When to use it
- Classwork: practice the Navy circumference body-fat formulas with fixed numbers.
- Rough fitness tracking illustration before talking to a clinician (not a diagnosis).
- Compare Navy vs Army labels on one page without a second URL.
Frequently asked questions
What formula does this use?
U.S. Navy / DoD-style log10 circumference formulas in inches after converting centimetre inputs.
Navy vs Army on this page?
Both are circumference estimators in the same family. Labels differ for search clarity; measurement discipline still matters more than the label.
Is this medical advice?
No. Results are educational estimates only and are not a diagnosis, treatment plan, or body-composition clinical test.
What about skinfold calipers?
Skinfold equations need multiple site readings and trained technique. They are explained here in FAQ, not as a separate thin tool URL.
Important notice
Body fat estimates are educational illustrations only and are not medical advice, diagnosis, or a substitute for clinical body-composition testing. Talk to a qualified clinician for health decisions.
References: U.S. Navy / DoD circumference method equations; ACE educational body-fat calculator notes; peer-reviewed circumference method literature.
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Questions or feedback
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