Body Fat Calculator - US Navy Method & Body Composition
Estimate body fat percentage using the US Navy circumference method. Enter waist, neck, and height — plus hip for women — to see body fat category and lean vs fat mass.
Body Measurements
US Navy method using waist, neck, and height.
Body Fat Estimate
Body Fat Percentage
17.5%
Fitness
Methodology and limitations
Last reviewed:
Methodology
Estimates body fat percentage using the U.S. Navy circumference method from height, waist, neck, and hip (women) measurements, then classifies the result into common body-fat categories.
Limitations
Circumference methods are estimates and depend on correct tape placement. They may be less accurate for very lean or very high body-fat individuals compared to DEXA or hydrostatic weighing.
Official sources
How Body Fat Percentage Is Estimated
Estimate body fat percentage using the US Navy circumference method. Enter waist, neck, and height — plus hip for women — to see body fat category and lean vs fat mass.
Method used
The calculator applies the U.S. Navy circumference formula using height, waist, and neck measurements (plus hip for women), converts the result to a body-fat percentage, and assigns a descriptive category.
Male %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76 (Navy method)
Practical example
A man who is 70 inches tall with a 34-inch waist and 15-inch neck might estimate body fat near 18%, classified in the fitness range on the calculator scale.
- Sex, height, waist circumference, neck circumference
- Hip circumference for women
- Imperial or metric measurements
The result shows body-fat percentage, category label, and estimated lean mass and fat mass in pounds.
Assumptions
- Measurements are taken at consistent anatomical landmarks.
- Waist must be larger than neck for a valid result.
- The Navy method is an estimate, not a clinical measurement.
What this includes
- Body-fat percentage, category, lean mass estimate, and fat mass estimate.
What this excludes
- DEXA scans, Bod Pod, hydrostatic weighing, bioimpedance devices, and body-composition prescriptions from a clinician.
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Frequently Asked Questions
How does the US Navy body fat method work?
The US Navy method uses circumference measurements and height in logarithmic formulas developed for military fitness assessments. It estimates body fat without calipers or scans.
How should I measure waist and neck?
Measure waist at navel level after a normal exhale. Measure neck just below the larynx with the tape snug but not compressing skin. Consistency matters more than tightness.
Why do women need a hip measurement?
The female formula accounts for hip circumference because fat distribution differs by sex. Men use waist and neck only.
How accurate is this compared to DEXA?
Circumference methods typically have a few percentage points of error versus DEXA scans. Use results for tracking trends over time rather than as a clinical diagnosis.
What body fat ranges are considered healthy?
For men, fitness range is often cited around 14-17%; for women, around 21-24%. Essential fat minimums are lower. Athletes and older adults may differ.