Estimate body fat percentage with the U.S. Navy method using waist, neck, height, and hip measurements in inches for men and women.
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Navy Body Fat Formula
The Navy body fat calculator uses the U.S. Navy circumference method. It estimates body fat percentage from body measurements in inches.
Men:
Body\ Fat\ \% = \frac{495}{1.0324 - 0.19077\log_{10}(Waist - Neck) + 0.15456\log_{10}(Height)} - 450Women:
Body\ Fat\ \% = \frac{495}{1.29579 - 0.35004\log_{10}(Waist + Hip - Neck) + 0.22100\log_{10}(Height)} - 450- Body Fat % is the estimated percentage of your body weight that is fat.
- Waist is your waist circumference in inches.
- Neck is your neck circumference in inches.
- Hip is your hip circumference in inches. This is used for women only.
- Height is your height in inches.
- log10 means base-10 logarithm.
The sex selection chooses the correct Navy formula. Men use waist, neck, and height. Women use waist, hip, neck, and height. The calculate function checks that the needed measurements are positive numbers, applies the correct formula, and returns body fat percentage rounded to two decimals. The reset function clears the fields. The calculation steps option shows the substituted values used in the formula.
Measurement Inputs Used by the Navy Method
| Measurement | Used for | How it affects the result |
|---|---|---|
| Waist | Men and women | A larger waist usually increases the estimated body fat percentage. |
| Neck | Men and women | A larger neck usually lowers the estimate because it is subtracted from the waist-related measurement. |
| Hip | Women only | A larger hip measurement usually increases the estimated body fat percentage. |
| Height | Men and women | Height adjusts the estimate for body size. |
General Body Fat Percentage Context
| Result | Men | Women |
|---|---|---|
| Very lean | About 6% to 13% | About 14% to 20% |
| Fit range | About 14% to 17% | About 21% to 24% |
| Average range | About 18% to 24% | About 25% to 31% |
| Higher range | About 25% and above | About 32% and above |
Example Calculations
Example 1: Male
- Waist: 36 in
- Neck: 16 in
- Height: 70 in
Using the men’s formula:
Body\ Fat\ \% = \frac{495}{1.0324 - 0.19077\log_{10}(36 - 16) + 0.15456\log_{10}(70)} - 450The estimated body fat percentage is about 18.57%.
Example 2: Female
- Waist: 30 in
- Hip: 40 in
- Neck: 13 in
- Height: 65 in
Using the women’s formula:
Body\ Fat\ \% = \frac{495}{1.29579 - 0.35004\log_{10}(30 + 40 - 13) + 0.22100\log_{10}(65)} - 450The estimated body fat percentage is about 30.97%.
FAQ
Is the Navy body fat formula exact?
No. It is an estimate based on circumference measurements. It can be useful for tracking changes over time, but it is not the same as a lab method such as DEXA, hydrostatic weighing, or a clinical body composition test.
Why does the calculator require hip measurement for women?
The Navy formula for women includes hip circumference. The women’s formula uses waist plus hip minus neck, then adjusts the result by height. The men’s formula does not use hip measurement.
What units should you enter?
Enter all measurements in inches. Do not mix inches and centimeters. If your measurements are in feet and inches, convert your full height to inches first. For example, 5 feet 10 inches is 70 inches.