Body Fat Calculator
Estimate your body-fat percentage from simple circumference measurements.
Uses the U.S. Navy (Hodgdon-Beckett) method, with a BMI-based cross-check and approximate fat / lean mass.
Your measurements
inches
inches
inches
inches
lb
Body fat (Navy method)
ACE category
Fat mass—
Lean mass—
BMI—
Est. body fat (BMI method)—
Enter height + weight to see the BMI-based estimate.
Decision guidance
- The Navy (Hodgdon-Beckett) method estimates body fat from neck, waist, and hip circumference — no body-weight input needed.
- For men, waist & neck alone are used; for women, hip is also required.
- The BMI cross-check needs weight (and age to refine the estimate) and is a rough second opinion.
- Tape-measure estimates carry roughly ±3–4% error versus clinical methods — use them as a tracking trend, not a diagnosis.
Worked reference: a 5'10", 180 lb man with a 34" waist and 15.5" neck runs roughly ~15–19% body fat.
ACE body-fat categories
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32%+ | 25%+ |
Data sources
Calculator.net — Body Fat Calculator · Omni Calculator — Navy Body Fat Calculator.
This is an estimate, not a medical diagnosis. Clinically precise measurement requires DEXA, bioelectrical impedance, or hydrostatic weighing. All math runs in your browser.