Body Fat Calculator

Body Fat Calculator

Estimate your body fat percentage from simple tape measurements using the U.S. Navy method — no calipers or scans required.

Sex
Height
ftin
Neck
in
Waist
in

Calculated instantly in your browser — nothing is sent to or stored on our servers.

How This Is Calculated

This calculator uses the U.S. Navy Circumference Method, developed for military body composition assessments. It estimates body fat from a few tape measurements instead of calipers or scans.

The Formula

Men: Body Fat% = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. Women: Body Fat% = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387.

For best accuracy, measure your neck just below the larynx, your waist at the navel, and (for women) your hips at their widest point — keep the tape snug but not compressing the skin.

Measurements matter more than false precision.

Measure consistently, without pulling the tape too tightly, and use repeated checks over time. This method estimates body fat and is not a medical measurement.