U.S. Navy (Hodgdon-Beckett) method Body-fat percentage reference ranges

Body Fat Percentage Calculator

Body fat estimate from the U.S. Navy circumference method.

Use this free body fat calculator to estimate your body fat percentage from simple tape measurements. It uses the U.S. Navy circumference method, supports both metric and imperial units, and classifies your result with general fitness category ranges.

Sex

Units

Height

Recheck

Neck

Recheck

Waist

Recheck

Hip

Recheck

Measure your neck below the larynx, your waist at the navel, and (for women) your hips at the widest point. Keep the tape snug but not compressing the skin.

Body Fat —%

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LeanFitnessAverageHigh

Enter your measurements to see a body-fat estimate.

Fitness range

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This calculator provides estimates based on published formulas and methodologies. Results are for educational and informational purposes only and should not be considered medical advice.

Understanding your result

Body fat percentage estimates the proportion of your total body weight that is fat tissue. Unlike BMI, it distinguishes fat from lean mass, so it is a more direct picture of body composition.

The U.S. Navy method estimates body fat from body circumferences (neck, waist, and — for women — hips) plus height. It is a practical, no-equipment estimate that correlates reasonably well with more expensive methods.

Body-fat percentage ranges vary by sex, age, and activity level. The categories here provide general fitness context, not a clinical diagnosis.

Methodology

Measurements are taken with a flexible tape: neck below the larynx, waist at the navel, and hips at the widest point for women. Imperial inputs are converted to centimetres before calculation.

The U.S. Navy equations use base-10 logarithms of the circumference differences and height to estimate body density, which is then converted to a body fat percentage.

Results are grouped into sex-specific fitness category ranges for easier interpretation.

The formula

The U.S. Navy method estimates body fat from log-transformed circumference measurements and height.

Men: %BF = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450

Women: %BF = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450

All circumferences and height are in centimetres (imperial inputs are converted internally).
For men the waist must be larger than the neck; for women waist + hip must exceed the neck, otherwise the estimate is undefined.

References

Frequently asked questions

How accurate is the U.S. Navy body fat calculator?

The U.S. Navy circumference method is a practical estimate that is typically within a few percentage points of more precise methods like DEXA or hydrostatic weighing. Accuracy depends on careful, consistent tape measurements. Treat the result as a useful estimate and trend tracker, not a clinical measurement.

What is a healthy body fat percentage?

Using general fitness ranges, the fitness range is roughly 14–17% for men and 21–24% for women, while the average range is 18–24% for men and 25–31% for women. Essential fat — the minimum needed for health — is about 2–5% for men and 10–13% for women.

What measurements do I need for the body fat calculator?

You need your height, neck circumference, and waist circumference. Women also need a hip measurement. Use a flexible tape measure, keep it snug but not compressing the skin, and measure at the same points each time for consistent tracking.

What is the difference between body fat percentage and BMI?

BMI compares your weight to your height but cannot tell fat from muscle, so a muscular person can read as overweight. Body fat percentage directly estimates how much of your body is fat tissue, making it a better measure of body composition.

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