Body Fat Percentage Calculator (Navy Method)

To use this body fat percentage calculator:

1. Select your gender (the formula differs for men and women).
2. Enter your age and weight in pounds.
3. Enter your height in total inches (for example, 5'10" = 70 inches).
4. Measure and enter your neck circumference at its narrowest point.
5. Measure and enter your waist circumference (at the navel for men, narrowest point for women).
6. If female, measure and enter your hip circumference at the widest point.

Results display instantly including your body fat percentage, fat mass, lean mass, fitness category, and BMI for reference.

A body fat calculator estimates the percentage of your total body weight that is composed of fat tissue. This calculator uses the U.S. Navy method, a widely accepted circumference-based formula developed by Hodgdon and Beckett at the Naval Health Research Center.

Unlike BMI, which only considers height and weight, body fat percentage provides a more meaningful assessment of body composition by distinguishing between fat mass and lean mass (muscle, bone, water, and organs). Two people with the same BMI can have vastly different body fat percentages depending on their muscle mass and fat distribution.

The U.S. Navy body fat formulas are:

• Men: Body Fat % = 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
• Women: Body Fat % = 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450

All measurements are in inches. The formula uses base-10 logarithms. Fat mass is calculated as Body Fat % × Weight / 100, and lean mass is Weight − Fat Mass.

Example 1 (Male): A 180 lb male, 70 inches tall, with a 15-inch neck and 34-inch waist: Body Fat % = 495 / (1.0324 − 0.19077 × log₁₀(34 − 15) + 0.15456 × log₁₀(70)) − 450 ≈ 17.7%. Fat mass ≈ 31.9 lbs. Lean mass ≈ 148.1 lbs. Category: Fitness.

Example 2 (Female): A 140 lb female, 65 inches tall, with a 13-inch neck, 28-inch waist, and 38-inch hip: Body Fat % = 495 / (1.29579 − 0.35004 × log₁₀(28 + 38 − 13) + 0.22100 × log₁₀(65)) − 450 ≈ 24.0%. Fat mass ≈ 33.6 lbs. Lean mass ≈ 106.4 lbs. Category: Fitness.