Body Fat Calculator

Estimate body fat percentage using the U.S. Navy circumference method.

Sex category used by the formula

The standard U.S. Navy equations use separate male and female formulas.

Height (inches)

Enter a value from 36 to 96 inches.

Neck circumference (inches)

Measure with a tape below the larynx, following standard measurement guidance.

Waist circumference (inches)

Keep the tape level and follow the measurement location recommended for the method.

Body weight (pounds)

Enter a value from 44 to 660 lb.

What Is Body Fat Percentage?

Body fat percentage is the proportion of total body weight estimated to consist of fat. Two people with the same body weight can have different amounts of fat and lean tissue.

This calculator uses the U.S. Navy circumference method. The estimate uses height, neck and waist measurements, plus hip circumference for the female equation.

Important: This tool is for general educational purposes. It is not a medical diagnosis and should not be used alone to make health or treatment decisions.

How to Measure Correctly

Height

Measure without shoes and enter the result in inches.

Neck

Use a flexible measuring tape and follow standard Navy-method measurement guidance. Keep the tape snug without compressing skin.

Waist

Measure at the location specified by the method and keep the tape level. Different measurement locations can change the estimate.

Hips

The female equation uses hip circumference, typically measured around the widest part of the hips.

Weight

Enter your current body weight in pounds.

Body Fat Calculation Formula

The U.S. Navy circumference equations estimate body fat percentage using base-10 logarithms of measurements in inches.

Men

Body fat % = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76

Women

Body fat % = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387

The equations return an estimate. Measurements must use consistent units, and results can be less reliable when measurements are inaccurate or outside the range for which the method is suitable.

Understanding Your Results

Estimated body fat: the calculated percentage of body weight attributed to fat.
Estimated fat mass: body weight multiplied by the estimated body-fat fraction.
Estimated lean body mass: body weight minus estimated fat mass. This includes water, muscle, bone and other non-fat tissues.

Fat mass = body weight × (body fat % ÷ 100)

Lean body mass = body weight − fat mass

Related Health & Fitness Calculators

Explore more free calculators for body composition, metabolism, calories, weight, hydration and nutrition.

Frequently Asked Questions

What does body fat percentage mean?

It estimates the proportion of total body weight that consists of fat. It does not describe every aspect of health or fitness.

What method does this calculator use?

It uses the U.S. Navy circumference equations with height, neck and waist measurements, plus hip circumference for the female equation.

Why is hip circumference required for women?

Hip circumference is one of the measurements included in the standard female equation.

Is the result exact?

No. It is an estimate based on body measurements. Results can differ from other body-composition assessment methods.

Can I use this calculator for medical decisions?

Do not rely on this estimate alone for medical decisions. Consult a qualified healthcare professional if you have concerns about your body composition or health.