Calculator
Body Fat Estimator
Explore an estimate of your body-fat percentage using the U.S. Navy tape-measure method.
Body Fat Estimator
Enter your measurements to estimate body fat.
This tool is for education and general interest only. It is not a medical device and must not be used to diagnose, treat or make health decisions. Always consult a qualified professional.
How to use it
- Step 1Select your sex.
- Step 2Measure and enter neck, waist (and hip) circumferences.
- Step 3Read your estimated body-fat percentage.
Body composition basics
Your body is made of more than just weight. Body composition describes how much of you is fat versus lean tissue like muscle, bone and water.
Some body fat is essential — it cushions organs, stores energy and supports hormones. The goal is a healthy balance, not zero fat.
The U.S. Navy method
This tool uses the U.S. Navy circumference formula, which estimates body fat from simple tape measurements. It is convenient but only an approximation.
More precise methods exist in clinics and labs. To learn about the biology, see our nutrition basics and exercise physiology guides.
Questions & Answers
Frequently asked questions
It is a reasonable estimate for education but can be off by several percentage points compared with lab methods.
It varies by age and sex, and healthy ranges differ for men and women. A professional can advise on what is right for you.
Measure the neck below the larynx, the waist at the navel, and (for women) the hips at the widest point.
Understand the science
Go beyond the numbers
Every tool pairs with a guide that explains the biology behind it in plain language.