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Online Medical Tools — Body Fat Calculator

Printed on 2/13/2026

For informational purposes only. This is not medical advice.


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Body Fat Calculator

The U.S. Navy body fat percentage formula uses circumference measurements to estimate body composition. It was developed by Hodgdon and Beckett at the Naval Health Research Center and is widely used by the military and fitness professionals as a simple, tape-measure-based alternative to more expensive methods like DEXA scans.

Formula: Male: 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.

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Frequently Asked Questions

How does the U.S. Navy body fat method work?

The Navy method estimates body fat percentage using circumference measurements of the neck, waist, and (for women) hips, along with height. It uses logarithmic equations developed by Hodgdon and Beckett. While not as precise as DEXA or hydrostatic weighing, it provides a reasonably accurate estimate with just a tape measure.

What is a healthy body fat percentage?

Healthy body fat ranges vary by sex. For men, 14–17% is considered fit and 18–24% is average. For women, 21–24% is fit and 25–31% is average. Essential fat minimums are about 2–5% for men and 10–13% for women. Athletes typically have lower body fat than the general population.

How accurate is the Navy body fat formula?

The Navy method has a standard error of about 3–4% compared to hydrostatic weighing. It tends to be more accurate for people with average body compositions and may be less reliable for very lean or very overweight individuals. For best results, measure consistently at the same time of day.

Where should I measure my waist and neck?

Measure your waist at the navel (belly button) level, keeping the tape horizontal. Measure your neck just below the larynx (Adam's apple), sloping slightly downward at the front. For hips (women), measure at the widest point of the buttocks. Keep the tape snug but not compressing the skin.