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Body Fat Calculator

Estimate body fat percentage with the legacy U.S. Navy circumference equation, using metric or imperial measurements and clear tape-placement guidance.

Gender

Units

Estimated body fat

16.9%

Tape-measure estimate, not a diagnosis

Estimated fat mass

11.9 kg

Estimated lean mass

58.1 kg

Body weight minus estimated fat mass

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How to use Body Fat Calculator

  1. 1Choose the male or female circumference equation and metric or imperial units.
  2. 2Enter height and neck. For the male equation measure abdomen at the navel; for the female equation enter natural waist and hips.
  3. 3Review the body-fat estimate. Weight is optional and only adds estimated fat and lean mass.

Useful tips

  • •Keep the tape level and snug without compressing the skin, and measure after a normal relaxed exhale where indicated.
  • •Repeat measurements under similar conditions if you are tracking a trend; small tape-position changes can move the estimate.
  • •This calculator uses the older circumference equation. Current official U.S. Navy BCA procedures changed in June 2026 and use a different process.

Frequently asked questions

Which measurements does the equation use?

The male equation uses height, neck and abdomen circumference at the navel. The female equation uses height, neck, natural waist and hip circumference.

Does weight change the body-fat percentage?

No. Weight is optional and is used only to estimate fat mass and lean mass after the body-fat percentage has been calculated.

Is this an official Navy BCA or a medical diagnosis?

No. It is a tape-measure estimate using the legacy circumference equations. Current official Navy BCA rules use a different process, and health decisions should use an appropriate professional assessment.