How does the Navy body fat calculator work?

The Navy method estimates body fat percentage from height, neck, waist, and for women hip measurements. It is an estimate, not a medical measurement.

Is the Navy body fat formula accurate?

It can be useful for tracking trends, but accuracy depends on consistent measurements and may vary from lab methods such as DEXA.

Can I use body fat percentage for FFMI?

Yes. FFMI uses body weight and body fat percentage to estimate lean body mass, then compares lean mass relative to height.

Navy method estimate

Body Fat Calculator

Estimate your body fat percentage from simple tape measurements, then use your result to calculate lean body mass and FFMI.

Default is Imperial. Metric is available if you prefer centimeters and kilograms.

BF%

Body fat estimate

LBM

Lean body mass

FFMI

Use result next

Body Fat Percentage Calculator

Your Body Fat Estimate

Uses the U.S. Navy circumference method.

Runs in your browser. No account required.

Tape method

Sex

Male Female

Units

Height ft

Height in

Weight lb

Neck in

Waist in

Auto-calculates

Metric & imperial units

Navy method estimate

Guide

How this body fat calculator works

This calculator uses the U.S. Navy circumference method. Men enter height, neck, and waist. Women enter height, neck, waist, and hips.

The calculator estimates body fat percentage, then uses your body weight to estimate lean body mass and fat mass. The result is useful for trend tracking and for entering a better body fat estimate into the FFMI calculator.

Any tape-measure formula has limitations. Hydration, posture, measuring location, and tape tension can change the result. Use the same measuring method each time and treat the output as an estimate.

How to Measure for a Better Estimate

The Navy method is only as consistent as your measurements. Use a soft tape, measure in the same conditions each time, and avoid pulling the tape so tight that it compresses the skin.

Waist

Measure around the abdomen at about navel level while standing relaxed. Do not suck in your stomach.

Neck

Measure below the Adam's apple, keeping the tape level and snug without pressing into the skin.

Hips

For women, measure around the widest part of the hips and glutes with feet together.

Timing

Measure at the same time of day, ideally before training and before a large meal, to reduce day-to-day noise.

Related Body Composition Guides

Use these next steps to compare body composition metrics and turn your body fat estimate into a better FFMI result.

Reference Chart Body Fat Percentage Chart → Compare common body fat ranges for men and women before interpreting your estimate. Body Composition FFMI vs BMI → See why BMI can be misleading when lean mass and body fat are changing. Next Step Calculate Your FFMI → Use your estimated body fat percentage to calculate lean mass and normalized FFMI.

Frequently Asked Questions

Where should I measure my waist?

For consistency, measure around the abdomen at about navel level. Keep the tape snug but not compressed.

Why do women need a hip measurement?

The Navy formula uses different equations for men and women. The female equation includes hip circumference.

Is this better than a DEXA scan?

No. DEXA and other lab methods can be more precise. This calculator is best used as a free estimate and tracking tool.

Can I use this result for FFMI?

Yes. FFMI needs body fat percentage to estimate lean mass. After estimating body fat here, use that number in the FFMI calculator.