Body Fat Calculator
Estimate body fat percentage
Quick guide
What can Body Fat Calculator help you do?
Free body fat calculator using the US Navy tape method. Estimate body fat percentage from height, neck, waist, and hip measurements.
Best for
Estimate a body-fat percentage from height and circumference measurements, using consistent measurements for your own calculation notes. This is not a body-fat scale reading. It accepts no photographs, body weight, or activity data, and does not supply health classifications or a body-composition diagnosis.
How to use it
Select sex and enter height, neck, and waist in centimeters. The female equation also requires hip circumference; the male equation ignores it. Defaults are male, 175, 38, 86, and 96 cm. Use positive measurements and a consistent measuring method rather than entering inches into these fields.
How to read the result
The male formula uses waist minus neck; the female formula uses waist plus hip minus neck. Logarithms of this value and height estimate density, then 495 divided by density minus 450 yields body-fat percentage. Only outputs from 0–75% are accepted; these are program bounds, not health categories.
Privacy and limits
Measurements and sex are used by browser-side arithmetic, without a measurement API, photo upload, or built-in health-record storage. Copying places the result in your clipboard. Analytics and possible advertising resources may still connect externally; check screenshots for measurements before sharing them.
The estimate is not a measurement or diagnosis, and measurement-site differences are not corrected. Error messages describe the selected equation: the female formula requires waist plus hip to exceed neck, not waist alone. Rejection at the output bounds is a formula limit, not a finding of illness.
Frequently Asked Questions
Which method is used?
This tool uses the US Navy circumference method.
Is it as accurate as a scan?
No. It is a convenient estimate and can differ from DEXA or clinical testing.