Health

Body Fat Calculator

A body fat percentage calculator using the U.S. Navy circumference method. Enter your neck, waist, and hip measurements (for women) to get an estimate of body fat, lean mass, and fat category.

Gender Male Female

Height (cm)

Neck circumference (cm)

Waist circumference (cm)

Hip circumference (cm) — women only

Body fat

19.5%

Fitness

Disclaimer. This is an estimate using the U.S. Navy circumference method. For clinical accuracy, consider DEXA scan or hydrostatic weighing. Consult a healthcare professional before making health decisions.

Method

How this calculator works

The U.S. Navy formula uses logarithmic equations with circumference measurements relative to height to estimate body fat percentage.

Male: BF% = 495 / (1.0324 − 0.19077×log₁₀(waist−neck)
             + 0.15456×log₁₀(height)) − 450

Female: BF% = 495 / (1.29579 − 0.35004×log₁₀(waist+hip−neck)
              + 0.22100×log₁₀(height)) − 450

All measurements in centimeters.

Select your gender.
Enter your height in cm.
Measure and enter neck circumference at the narrowest point.
Measure and enter waist circumference at navel level.
For women: measure and enter hip circumference at the widest point.
The calculator applies the Navy formula and classifies your body fat category.

Examples

Worked examples

Real numbers, end-to-end results.

Male · 175cm · Neck 38cm · Waist 85cm

~19.5% · Fitness

Typical fit male — within healthy range.

Female · 165cm · Neck 32cm · Waist 70cm · Hip 95cm

~25% · Fitness

Healthy female range.

Male · 180cm · Neck 42cm · Waist 100cm

~24% · Average

Approaching overweight threshold.

Use cases

When to use it

Track body composition changes during fitness programs.
Get a more meaningful metric than BMI alone.
Set realistic fat-loss or muscle-gain targets.
Military and fitness professionals assessing body standards.

FAQ

Frequently asked questions

What is the U.S. Navy body fat method?

The U.S. Navy method estimates body fat using circumference measurements (neck, waist, and hip for women) along with height. It is used by the military for fitness standards and is surprisingly accurate for most people.

How accurate is the Navy body fat calculator?

Studies show it is within ±3–4% of DEXA scans for most adults. It tends to be less accurate for very lean individuals or those with unusual body proportions.

What is a healthy body fat percentage?

For men: 6–24% (athletic: 6–13%, fitness: 14–17%, average: 18–24%). For women: 14–31% (athletic: 14–20%, fitness: 21–24%, average: 25–31%). Below essential fat levels is dangerous.

Where should I measure my waist?

Measure at the navel (belly button) level for men. For women, measure at the natural waist (narrowest point). Keep the tape horizontal and measure on bare skin.

Why is hip measurement needed for women but not men?

Women naturally store more fat around the hips. The Navy formula accounts for this gender difference by including hip circumference in the female equation for more accurate results.

Is body fat percentage better than BMI?

Generally yes. BMI does not distinguish between muscle and fat, so a muscular person may have a high BMI but low body fat. Body fat percentage gives a more accurate picture of health.