C vs Ce on Calculator

by
Expertly reviewed by David Chen, MS, CSCS • Updated October 2023. Certified Fitness Specialist and Health Analytics Expert.

This professional Navy BMI and Body Fat Calculator provides an estimate of your body fat percentage based on the official U.S. Navy circumference method.

Navy BMI Calculator

Estimated Body Fat Percentage
0.0%
BMI: —
Please enter valid positive numbers for all fields.

Navy BMI Calculator Formula

The U.S. Navy uses specific equations to estimate body fat percentage without expensive scans. These formulas use log functions of body circumferences.

Male: 495 / (1.03248 – 0.19077 × log10(Waist – Neck) + 0.15456 × log10(Height)) – 450

Female: 495 / (1.29579 – 0.35004 × log10(Waist + Hips – Neck) + 0.22100 × log10(Height)) – 450
Source: Military Health System (Health.mil)

Variables:

  • Gender: Biological sex determines which biological constant to use.
  • Height: Your standing height in centimeters.
  • Neck: Circumference measured just below the larynx.
  • Waist: Measured at the narrowest point (females) or navel (males).
  • Hips: (Females only) Measured at the widest part of the buttocks.

Related Calculators

Explore more fitness tools to track your progress:

What is the Navy BMI Calculator?

The Navy BMI Calculator is a misnomer often used to describe the Navy Body Fat Percentage formula. Unlike a standard Body Mass Index (BMI) which only compares height to weight, the Navy method assesses body composition by measuring specific circumferences where fat tends to accumulate.

This method is crucial for service members because it determines eligibility for duty. If a service member exceeds the standard BMI weight-for-height table, they are “taped” using these measurements to see if their body fat falls within acceptable limits.

How to Calculate Navy BMI (Example)

Let’s calculate for a male with Height: 180cm, Waist: 90cm, and Neck: 40cm:

  1. Find the difference between Waist and Neck: 90 – 40 = 50.
  2. Calculate Log10(50) = 1.6989.
  3. Calculate Log10(180) = 2.2553.
  4. Apply the Male Constant: 1.03248 – (0.19077 * 1.6989) + (0.15456 * 2.2553) = 1.0569.
  5. Final Body Fat: (495 / 1.0569) – 450 = 18.3%.

Frequently Asked Questions (FAQ)

Is the Navy Body Fat Calculator accurate?

While not as precise as a DEXA scan, it has a margin of error of about 3-4%, making it one of the most reliable field-testing methods available.

Why is my Navy BF percentage different from my BMI?

BMI measures density (mass/height), whereas the Navy formula measures volume and distribution. Muscular individuals often have high BMIs but low Navy body fat percentages.

How often should I measure?

It is recommended to measure once every month under similar conditions (e.g., in the morning before breakfast) to track trends.

Does this apply to civilians?

Yes, although designed for military standards, anyone can use this formula as a cost-effective way to estimate body composition changes.