Body Fat % Calculator

Estimate body fat percentage using the US Navy method.

Overview

Estimates total body fat percentage using the anthropometric US Navy circumference method based on neck, waist, and hip circumference measurements.

Formula & Calculation Method

Navy Formula (Men) = 495 / [1.0324 - 0.19077×log10(Waist - Neck) + 0.15456×log10(Height)] - 450

For women, formula incorporates hip circumference: [Waist + Hip - Neck]. Categorizes essential fat, athletic, fitness, acceptable, and obesity ranges.

Worked Example: Adult Male (Height 178 cm, Neck 38 cm, Waist 86 cm)

Inputs: Sex = Male | Height = 178 cm | Neck = 38 cm | Waist = 86 cm

  • Waist minus Neck circumference = 86 - 38 = 48 cm
  • Logarithmic evaluation of circumference difference and height
  • Estimated Body Fat % = 16.4%
  • Fitness category = Fitness Range (14%–17%)

Summary: Height = 178 cm | Waist = 86 cm | Body Fat % = 16.4% | Category = Fitness Range

Common Use Cases

  • Body Recomposition Monitoring: Track fat loss while verifying that resistance training preserves lean skeletal muscle.
  • Athletic Conditioning: Monitor competition readiness for sports with weight classes (wrestling, boxing, rowing).
  • Health Risk Stratification: Assess visceral adiposity risks associated with metabolic syndrome.

Frequently Asked Questions

What is an ideal body fat percentage for men and women?

For men: Athletic (6-13%), Fitness (14-17%), Acceptable (18-24%). For women: Athletic (14-20%), Fitness (21-24%), Acceptable (25-31%).

What is essential body fat?

The minimal fat required for physiological survival, nerve insulation, and organ protection: roughly 2-5% for men and 10-13% for women.

Where should waist circumference be measured?

Men should measure horizontally across the navel; women should measure at the narrowest point of the natural waist above the hip bones.

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