Body Fat Percentage Calculator

What is the Body Fat Percentage Calculator?

This tool estimates body fat percentage using the U.S. Navy circumference method, developed by the Navy as a fast, equipment-free alternative to skinfold calipers or DEXA scans — it only needs a measuring tape and a few circumference readings.

The formula

For men: %BF = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. For women: %BF = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387. All measurements are in inches.

How to measure accurately

1. Neck: just below the larynx, tape sloping slightly downward toward the front.
2. Waist (men): horizontally at the navel. Waist (women): at the narrowest point.
3. Hip (women only): at the widest point of the hips/buttocks.

This is an estimate, not a diagnostic measurement — the Navy method is accurate to within a few percentage points for most people but can be less reliable for very lean, very large, or unusually proportioned bodies. For a precise reading, a DEXA scan or hydrostatic weighing remains the clinical standard.