About

Determining body composition offers a superior metric for health than weight alone. While scales reflect total mass they cannot distinguish between muscle tissue and adipose tissue. This tool utilizes the U.S. Navy formulation which relies on anthropometric circumference measurements to estimate body density. This method is widely respected for its balance between accessibility and accuracy without requiring expensive equipment like DEXA scans or hydrostatic weighing. Understanding your body fat percentage helps in setting realistic fitness goals and assessing metabolic risk factors associated with visceral fat storage.

Formulas

The calculator employs the U.S. Navy Circumference method. The formulas differ by biological sex due to physiological differences in fat distribution.

For Men:

BF = 86.010 × log₁₀(abdomen − neck) − 70.041 × log₁₀(height) + 36.76

For Women:

BF = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387

Reference Data

Classification	Women %	Men %
Essential Fat	10 to 13	2 to 5
Athletes	14 to 20	6 to 13
Fitness	21 to 24	14 to 17
Average	25 to 31	18 to 24
Obese	≥ 32	≥ 25

Frequently Asked Questions

The US Navy method generally has a margin of error of around 3-4% when compared to hydrostatic weighing. Accuracy depends heavily on the precision of your measurements. The tape should be taut but not compressing the skin.

For men measure at the navel. For women measure at the narrowest part of the torso between the ribs and the hips. Incorrect placement is the most common cause of error.

Women biologically store more adipose tissue in the gluteal-femoral region due to hormonal factors. Including hip circumference provides a more accurate estimate of total body density for female physiology.

Unlike bioimpedance scales that send electrical signals through the body tape measure calculations are not significantly affected by hydration levels. This makes them more consistent for daily or weekly tracking.