How to use the Body Fat Calculator
- Measure with a flexible tape, snug but not compressing the skin.
- Neck: just below the larynx. Waist: horizontally at the navel (men) or the narrowest point (women). Hips (women): widest part of the buttocks.
- Enter height and measurements, and optionally your weight to see fat and lean mass.
How it works
The U.S. Navy method estimates body fat from circumferences (all in inches):
Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
Categories follow the American Council on Exercise (ACE) ranges. Expect an error of a few percentage points compared with DEXA scans.
Frequently asked questions
How accurate is the Navy body fat method?
It is usually within about 3–4 percentage points of laboratory methods for most people, which makes it useful for tracking change over time with consistent measurements.
What is a healthy body fat percentage?
ACE considers roughly 14–24% fit-to-average for men under the 'average' cut-off of 25%, and 21–31% for women. Essential fat is about 2–5% for men and 10–13% for women.
Is body fat better than BMI?
Body fat percentage separates fat from muscle, so it can be more informative for athletic people. BMI is simpler and is still widely used for screening.