Body Fat Calculator
Estimate body fat percentage from tape-measure measurements (U.S. Navy method).
Enter your values to calculate your result.
Formula
U.S. Navy circumference method (see formulaExplanation for the full equation)
Men: %BF = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450. Women: %BF = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450. All measurements in centimeters. This estimates body fat from tape-measure circumferences instead of calipers or a scan.
Example
A man with a 178 cm height, 38 cm neck, and 85 cm waist has an estimated body fat of about 16.4%.
Frequently Asked Questions
Why does the formula need a hip measurement for women but not men?
The U.S. Navy method uses different equations for men and women because fat distribution differs by sex — the women's formula additionally accounts for hip circumference.
How accurate is this method?
It's a reasonable estimate for most people (typically within a few percentage points of more precise methods), but measurement technique matters — measure at the same time of day, without clothing, with the tape snug but not compressing the skin.