Guide
How Body Fat Percentage Is Estimated (U.S. Navy Method)
Learn how the U.S. Navy method estimates body fat from measurements, its accuracy, and how to take good measurements.
A body fat calculator estimates your body fat percentage from circumference measurements using the U.S. Navy method. It is a practical alternative to lab equipment when you want a repeatable home estimate.
The U.S. Navy method
The method uses height plus a few circumference measurements — neck and waist for men; neck, waist, and hip for women — in a formula that estimates body fat percentage. It is based on the assumption that fat tends to collect at the waist, while a larger neck often reflects lean mass.
How to take measurements
- Measure the neck just below the larynx, keeping the tape level.
- Measure the waist at the navel, relaxed, not pulled in.
- Women: measure the hip at the widest point.
- Use a soft tape and measure in the same spots each time for consistency.
How to use the calculator
- Enter your sex, height, and the measurements.
- Read the estimated body fat percentage and category.
- Track the trend over time rather than fixating on one number.
Examples
A man 178 cm tall with a 40 cm neck and 86 cm waist might estimate around 18% body fat. A woman 165 cm tall with a 34 cm neck, 76 cm waist, and 99 cm hips might estimate around 27%. Healthy ranges differ by sex: roughly 10–20% for men and 18–28% for women.
Accuracy and limitations
The Navy method is convenient and repeatable at home, but it is an estimate and can be off by a few percentage points compared to lab methods like DEXA or hydrostatic weighing. Tape placement and posture change the result, so measure consistently. Use the figure to track trends over weeks, not as an exact measurement.
Put it into practice
Use the Body Fat Percentage Calculator right now — free, in your browser, no sign-up required.
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