Body Fat Calculator
Estimate your body fat percentage using the US Navy method or BMI formula. See your fat mass, lean mass, and category.
About this tool
Estimate your body fat percentage using the US Navy circumference method or a BMI-based fallback formula. Get your body fat category (Essential, Athletes, Fitness, Average, or Obese), fat mass, and lean mass in both metric and imperial units. Visual gauge shows where you fall on the body fat spectrum.
How to use it
Quick steps to get the most out of this utility.
- 1
Choose your method
Select US Navy Method for higher accuracy or BMI-based if you only have height and weight.
- 2
Enter your measurements
For Navy method: enter height, weight, neck, waist, and hip (women only). For BMI method: enter height, weight, and age.
- 3
Read your results
See your body fat percentage, category, fat mass, and lean mass with a visual gauge.
Understanding body fat percentage
Body fat percentage is the proportion of your total body weight that is fat tissue. Unlike BMI, which only uses height and weight, body fat measurement accounts for the actual composition of your body. Two people at the same weight can have dramatically different fat percentages — a muscular athlete may score as overweight on BMI while having very low body fat.
The US Navy method (also called the US Navy circumference method) was developed by the US Navy in the 1980s as a practical way to estimate body fat without expensive equipment. It uses a series of circumference measurements combined with height in a regression equation. While not as accurate as DEXA scans or hydrostatic weighing, it provides a reasonable population-level estimate for most people.
Frequently asked questions
How is body fat percentage measured?+
This calculator uses two methods: the US Navy method uses neck, waist, and hip measurements in a regression formula. The BMI-based method estimates body fat from your BMI, age, and sex. Neither method is as accurate as DEXA scans or hydrostatic weighing, but both provide useful estimates.
What is a healthy body fat percentage?+
For men, 6–17% is considered fitness/athletic range, 18–24% is average, and 25%+ is in the obese range. For women, 14–20% is athletic, 21–31% is average, and 32%+ is obese. Essential fat (needed for organ function) is 2–5% for men and 10–13% for women.
Should I use the Navy method or BMI-based method?+
The US Navy method is generally more accurate because it uses circumference measurements that correlate with fat distribution. The BMI-based method is a rougher estimate useful when you only have weight and height. If you can take the measurements accurately, use the Navy method.
What is the difference between fat mass and lean mass?+
Fat mass is the weight of all body fat. Lean mass includes muscles, bones, organs, and water. Knowing both helps you understand your body composition beyond just weight — two people with the same weight can have very different fat vs lean ratios.
How do I measure my waist and neck accurately?+
Use a flexible tape measure (like a tailoring tape). For neck, measure the narrowest point below the Adam's apple. For waist, stand relaxed and measure at navel height (men) or the narrowest point (women). Keep the tape parallel to the floor and snug but not compressing skin.
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