Body Fat Calculator (US Navy)
Estimate body fat percentage from tape measurements (US Navy method).
Estimate your body fat percentage using the US Navy circumference method — just a tape measure, no special equipment. Enter your measurements in centimeters. It is an estimate, not a clinical measurement.
Formula / method
Examples
≈ 19%
≈ 26%
The US Navy method
This calculator estimates body fat from simple tape measurements — neck, waist and, for women, hips — plus height, using the US Navy circumference formula. It needs no special equipment, which makes it a practical alternative to calipers or scales that only show weight.
Accuracy and what it is good for
Circumference estimates are approximate and work best for tracking change over time rather than as an exact percentage. Measure consistently — same time of day, tape snug but not tight — so trends are meaningful. Unlike BMI, this method distinguishes fat from overall weight, which is why it complements the BMI Calculator.
Where it's used
- Tracking body-fat change over time with only a tape measure, no calipers or scale
- Service members checking against military body-composition standards
- A quick fitness starting point when a DEXA scan isn't practical
- Complementing BMI by separating fat from overall weight
- Monitoring progress through a cut or a bulk
Real-world examples
- A man 178 cm tall with a 38 cm neck and 90 cm waist estimates at roughly 19% body fat.
- A woman 165 cm tall with neck 32 cm, waist 75 cm and hip 95 cm estimates at about 26%.
- Measured monthly, a lifter sees waist drop 3 cm while neck holds steady, and the estimate falls even though scale weight is flat.
A bit of history
The circumference formula was developed by researchers J. A. Hodgdon and M. B. Beckett at the US Naval Health Research Center in San Diego in 1984, derived from underwater-weighing data on Navy personnel, and it remains the basis of the Navy's body-composition standards.
FAQ
Is the hip measurement always needed?
Only for women — the female formula uses neck, waist and hip. The male formula uses neck and waist only, so the hip field is ignored for men.