Home/Tools/Body Fat Calculator

Body Fat Calculator with a Tape Measure

Paul Hummel Last reviewed October 6, 2026 4 min read
Calculator

Body fat with a tape measure

Navy method by Hodgdon & Beckett (1984).

Estimated body fat
0%
Fat mass
–
Fat-free mass
–
Next: calculate FFMI and natural limit → Get the app – track training and body in one place →
Estimate using the Navy method. Tape measurement errors change the result.
Quick answer

The Navy method estimates body fat from neck, waist (plus hips for women) and height. For men, Hodgdon and Beckett (1984) report a standard error of estimate of 3.52 percentage points.

How to measure

You need a flexible tape measure and your height. The neck is measured just below the larynx. Men measure the waist at navel level; women additionally measure the hips at the widest point of the buttocks. The tape should sit snugly without compressing the skin; measure relaxed after breathing out.

How the Navy method works

Hodgdon and Beckett (1984) developed equations for the U.S. Navy that estimate body density from circumferences and height. Body density is then converted into body fat percentage using the Siri equation. For men, waist and neck are used; for women, waist, hips and neck.

For the men's equation, Hodgdon and Beckett (1984) report a standard error of estimate of 3.52 percentage points of body fat. Treat the result as an approximation and always measure the same way to track trends.

Make progress visible

GymLog AI logs training, meals and weight via chat – no forms, no lists.

Download on the App StoreGet it on Google Play

Related questions

Sources

  1. Hodgdon, J. A. & Beckett, M. B. (1984). Prediction of Percent Body Fat for U.S. Navy Men from Body Circumferences and Height. Naval Health Research Center. DTIC
  2. Hodgdon, J. A. & Beckett, M. B. (1984). Prediction of Percent Body Fat for U.S. Navy Women from Body Circumferences and Height. Naval Health Research Center. DTIC
This content is for general informational purposes only and is not a substitute for medical advice. Results from equations are estimates and may vary individually.