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Weight & Body tool

Body Fat Calculator

Estimate your body fat percentage from your height, neck, waist and hip measurements with the US Navy method, plus fat and lean mass. Free, nothing stored.

Nothing you enter leaves your device.

Inputs

Measure the neck just below the larynx, the waist at the navel (men) or its narrowest point (women), and the hips at their widest point.

Results

Enter values to see your results.

Simple steps

How it works

  1. 01

    Choose your units and sex, and enter your height.

  2. 02

    Measure and enter your neck and waist, and your hips if you are a woman.

  3. 03

    Select Calculate to see your body fat percentage and its category.

Good to know

Frequently asked questions

How do I measure correctly?

Use a soft tape, stand relaxed and do not pull the tape tight. Measure the neck just below the larynx, the waist at the navel for men or at its narrowest point for women, and the hips at their widest point.

How accurate is the US Navy method?

It is usually within about 3 to 4 percentage points of laboratory methods, if the measurements are careful. Take each measurement twice and use the average.

What do the categories mean?

They follow the American Council on Exercise: essential fat, athletes, fitness, average and above average, with different ranges for men and women.

Why do I need to enter my weight?

You do not. With your weight, the calculator also shows how much of it is fat and how much is lean mass.

Can I use inches?

Yes. Choose imperial units and enter all measurements in inches.

Does it work for everyone?

It is designed for adults. It is less reliable for very muscular people, during pregnancy and for older adults.

Is anything I enter stored or sent?

No. The calculation runs in your browser. Nothing you type is saved or sent to a server.

How it is calculated

US Navy method (Hodgdon and Beckett), measurements in cm. Men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. Women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.221 × log10(height)) − 450. Categories follow the American Council on Exercise.

Sources

  • Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center, reports 84-11 and 84-29, 1984
  • American Council on Exercise. Body fat percentage categories

Last reviewed: October 14, 2026

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