Body Fat Calculator (US Navy)
Estimate body fat from neck, waist, and hip measurements (US Navy method).
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Not a substitute for clinical assessment methods.
Understanding your result
The percentage is an estimate of how much of your body weight is fat. Healthy ranges differ by gender, often around 10–24% for men and 20–31% for women. Athletes may be lower. Use it as one of several tools, not a diagnosis.
Want context on what this body-fat estimate means for your decisions?Read the guide →How it's calculated
The US Navy formula uses circumference measurements: height, neck, waist, and for women also hip. Different logarithmic equations are used for men and women. It gives a useful estimate when measurements are taken consistently at the same body points.
Lengths are in centimeters; log10 is base-10 logarithm (same coefficients as in our code). The form converts inches when needed.
Body fat categories (reference)
General reference ranges. Guidelines vary by source and gender. Ours follow the same idea:
| Category | Body fat % range |
|---|---|
| Essential fat | < 5% |
| Athletes | 5 – 14% |
| Fitness | 14 – 18% |
| Average | 18 – 25% |
| Above average | 25 – 32% |
| Obese | > 32% |
Reference ranges for women (sources vary):
| Category | Body fat % range |
|---|---|
| Essential fat | < 13% |
| Athletes | 13 – 20% |
| Fitness | 20 – 24% |
| Average | 24 – 31% |
| Above average | 31 – 38% |
| Obese | > 38% |
Measurement tips
Use a soft tape at the same points each time: waist at navel level, neck below the larynx. For women, hip at the widest part. Measure in the same conditions (e.g. morning, before eating) for consistent tracking over time.
FAQ
What is a healthy body fat percentage?
Guidelines vary. Often 10–20% for men and 20–30% for women is considered in a healthy range. Athletes may be lower. Very low body fat can affect health.
Is this as accurate as a DEXA scan?
No. DEXA and other professional methods are more accurate. This calculator gives a rough estimate useful for tracking trends when measured the same way over time.