Body Fat Calculator

Estimate your body fat percentage with the U.S. Navy method, using a tape measure and your height and weight.

Sex

Just below the Adam's apple (larynx).

Around the belly, level with the navel.

What is body fat percentage?

Body fat percentage is the share of your total body weight that is fat. Unlike BMI, which only compares weight to height, it separates fat from everything else — muscle, bone, organs, and water, together called lean mass. Two people with the same weight and BMI can have very different body fat percentages, so it's a more direct measure of body composition.

How the U.S. Navy method works

The U.S. Navy method was developed by Hodgdon and Beckett at the Naval Health Research Center in 1984 so body fat could be checked with only a tape measure. It estimates body fat from circumference measurements and height, using separate equations for men and women (all measurements in centimeters):

Men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450

Women: 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450

US measurements are converted to centimeters first, so both unit systems give the same result. Your weight is then split into fat mass and lean mass using the estimated percentage.

How to measure

Use a flexible tape measure against bare skin. Keep it snug but not pressing into the skin, stand relaxed, and don't hold your stomach in.

  • Neck: just below the Adam's apple (larynx), with the tape sloping slightly down toward the front.
  • Waist (men): horizontally around the belly, level with the navel, at the end of a normal breath out.
  • Waist (women): at the narrowest point of the waist, usually a little above the navel.
  • Hip (women): around the widest part of the hips and buttocks.

Measure each spot two or three times and use the average. For tracking progress, measure at the same time of day, ideally in the morning before eating.

Understanding the categories

The results table uses categories from the American Council on Exercise (ACE). For men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, acceptable 18–24%, and obesity 25% or higher. For women: essential fat 10–13%, athletes 14–20%, fitness 21–24%, acceptable 25–31%, and obesity 32% or higher. Women naturally carry more essential fat than men, which is why the ranges are higher.

Limitations

The Navy method is an estimate. Results can differ from lab methods like DEXA scans by several percentage points, and it tends to be less accurate for very lean or very muscular people and for people with obesity. Small measuring errors — especially at the waist — change the result noticeably, so the method is most useful for tracking trends with consistent measuring. It isn't a diagnosis; see the Disclaimer and compare with the BMI Calculator for another reference point.

Read the science

References

The formulas and figures on this page come from these sources. Our Editorial Policy explains how they're chosen and checked.

  • U.S. Navy equation for men: Hodgdon, J. A., & Beckett, M. B. (1984). Prediction of percent body fat for U.S. Navy men from body circumferences and height (Report No. 84-11). Naval Health Research Center. Link
  • U.S. Navy equation for women: Hodgdon, J. A., & Beckett, M. B. (1984). Prediction of percent body fat for U.S. Navy women from body circumferences and height (Report No. 84-29). Naval Health Research Center. Link
  • Body fat categories: American Council on Exercise. Percent body fat norms for men and women. In Percent body fat calculator (archived 1 December 2023). Link
  • Accuracy of tape-measure methods: Potter, A. W., Tharion, W. J., Holden, L. D., Pazmino, A., Looney, D. P., & Friedl, K. E. (2022). Circumference-based predictions of body fat revisited: Preliminary results from a US Marine Corps body composition survey. Frontiers in Physiology, 13, 868627. doi:10.3389/fphys.2022.868627