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Body Fat Calculator

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

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About this calculator

Estimate your body fat percentage from simple tape-measure circumferences, using the U.S. Navy method.

How to use

  1. Choose US, Metric, or Other units, whichever matches your tape measure.
  2. Select your gender, and enter your age, weight, and height.
  3. Enter your neck and waist circumference (and hip circumference, if female).
  4. Press Calculate to see your estimated body fat percentage, category, and fat/lean mass.

Tips

  • The Navy method is a quick estimate, not as accurate as DEXA scans, hydrostatic weighing, or skinfold calipers — use it to track trends over time rather than as a precise measurement.
  • Measure your waist at your navel and your neck just below the larynx for the most consistent results.
  • Age and weight do not directly affect the body fat percentage formula — they are used only to compute fat mass and lean mass.

Formula

For men: Body Fat % = 495 ÷ (1.0324 − 0.19077×log10(waist − neck) + 0.15456×log10(height)) − 450 For women: Body Fat % = 495 ÷ (1.29579 − 0.35004×log10(waist + hip − neck) + 0.22100×log10(height)) − 450 where waist, neck, hip, and height are all measured in centimeters.