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Body Fat Percentage Calculator

Last updated: July 11, 2026

Estimate your body fat percentage using the U.S. Navy method based on body circumference measurements. Calculate your fat mass, lean mass, and determine your body fat category.

How to Use This Calculator

  1. Select your Gender (Male or Female).
  2. Enter your Age, Weight (kg), and Height (cm).
  3. Measure your Neck and Waist circumference in cm (and Hip for females). Use a flexible tape measure, keeping it level and snug but not tight.
  4. Click Calculate to see your body fat percentage, category, fat mass, and lean mass.

Formula

Male (U.S. Navy):

BF% = 495 / (1.0324 − 0.19077 × log₁₊(waist − neck) + 0.15456 × log₁₊(height)) − 450

Female (U.S. Navy):

BF% = 495 / (1.29579 − 0.35004 × log₁₊(waist + hip − neck) + 0.22100 × log₁₊(height)) − 450

Examples

Athletic male:

Waist 80cm, neck 38cm, height 180cm → ~12% body fat (Athlete category).

Average male:

Waist 95cm, neck 40cm, height 175cm → ~22% body fat (Average category).

Fitness female:

Waist 70cm, hip 95cm, neck 33cm, height 165cm → ~22% body fat (Fitness category).

Frequently Asked Questions

What are the body fat categories?

For men: Essential 2–5%, Athletes 6–13%, Fitness 14–17%, Average 18–24%, Obese 25%+. For women: Essential 10–13%, Athletes 14–20%, Fitness 21–24%, Average 25–31%, Obese 32%+.

How accurate is the Navy method?

It's reasonably accurate (±3–4%) for most people and is a practical, non-invasive method. DEXA scans and hydrostatic weighing are more accurate but less accessible.

Where should I measure my waist?

Measure horizontally at the narrowest point of the torso, typically at or near the navel level. Keep the tape level all around.

Is body fat percentage more important than BMI?

For many people, yes. BMI doesn't distinguish between muscle and fat. Body fat percentage gives a better picture of overall health and fitness.

Disclaimer: The U.S. Navy method provides estimates with an accuracy of approximately ±3–4%. For clinical-grade body composition analysis, consult a healthcare professional for methods like DEXA scanning.