How the US Navy body fat formula works
The US Navy method estimates body fat from your height and a few circumference measurements. It was
developed by the US Naval Health Research Center and is still used by the US military. All you need
is a tape measure.
The formulas (measurements in inches)
Men: 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76
Women: 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387
If you enter centimeters, the calculator converts them to inches first.
Body fat categories
Source: American Council on Exercise. For a different view of your weight, try the BMI calculator.
Frequently asked questions
How do I measure for the Navy body fat method?
Use a flexible tape measure on bare skin, keeping it level and snug without compressing the skin. Measure your neck just below the larynx, your waist at the navel for men or the narrowest point for women, and (women only) your hips at the widest point. Take each measurement twice and use the average.
How accurate is the US Navy method?
It's typically within about 3–4 percentage points of more precise methods such as DEXA scans, as long as you measure carefully. It's a good, free way to track changes over time.
What is a healthy body fat percentage?
According to the American Council on Exercise, average ranges are about 18–24% for men and 25–31% for women. Athletes are usually lower, at 6–13% for men and 14–20% for women. Essential fat, the minimum needed for health, is 2–5% for men and 10–13% for women.
Why does the calculator ask for hip size only for women?
The US Navy formulas were developed separately for men and women. Women tend to store more fat around the hips, so the female formula includes the hip measurement to improve accuracy.
