US Navy Body Fat Calculator

How to use

1. Select your biological sex.
2. Enter current weight (kg) and standing height (cm).
3. Measure neck circumference just below the Adam's apple.
4. Measure waist circumference at the navel level on a relaxed exhalation.
5. For females, enter hip circumference at the widest point around buttocks.
6. View body fat percentage, total fat mass, and lean muscle mass in kilograms.

Why the US Navy formula is superior to BMI

The US Navy body composition assessment was engineered for military fitness readiness tests, requiring no clinical laboratory gear.

Unlike BMI which relies exclusively on scale weight and mistakenly labels muscular athletes as overweight, the US Navy formula leverages circumference proportions to accurately differentiate adipose tissue from lean muscle.

Body fat norms and classification (ACE guidelines)

• Essential Fat: 2–5% (men) / 10–13% (women).
• Athletes: 6–13% (men) / 14–20% (women).
• Fitness Standard: 14–17% (men) / 21–24% (women).
• Acceptable Range: 18–24% (men) / 25–31% (women).
• Obese: 25%+ (men) / 32%+ (women).

Accurate tape measuring protocols

• Neck: Measure horizontally just below the larynx, keeping tape flat without tightening.
• Waist (Men): Measure horizontally across the umbilicus (navel) after normal exhalation.
• Waist (Women): Measure at the narrowest natural waistline.
• Hips (Women): Measure at the widest transverse diameter of the buttocks.

Fat mass vs Lean Body Mass (LBM)

Your total weight comprises Fat Mass and Lean Body Mass (contractile muscle, bones, connective tissue, internal organs, and water).

Sustainable body recomposition aims to lower fat mass while preserving lean muscle through resistance stimulus and adequate protein.