Body Fat Calculator
Estimate your body fat percentage using the US Navy method with neck, waist, and hip measurements. See your category and lean body mass.
About Body Fat Calculator
Body fat percentage is one of the most useful indicators of overall fitness and health. Unlike BMI, which only considers height and weight, body fat percentage tells you what portion of your weight comes from fat versus lean tissue like muscle and bone.
The US Navy Method
This calculator uses the US Navy circumference method, a well-established formula developed by the United States Navy for fitness assessments. It requires simple tape measurements of your neck, waist, and hips (for women), along with your height. The formula uses logarithmic calculations to produce a body fat estimate.
Body Fat Categories
Your result is classified into one of five categories: essential fat, athlete, fitness, average, or obese. These categories differ for men and women, reflecting natural differences in fat distribution. Essential fat is the minimum needed for basic health, while the athlete and fitness ranges indicate above-average leanness.
Lean Body Mass
The calculator also shows your estimated lean body mass - your total weight minus fat weight. This figure is helpful for tracking changes in body composition over time, especially if you are gaining muscle while losing fat and your scale weight stays the same.
Metric and Imperial Support
You can enter your measurements in centimeters and kilograms or in inches and pounds. The calculator handles all conversions automatically.
Privacy
All calculations run entirely in your browser. Your measurements are never sent to any server or stored anywhere.
Frequently Asked Questions
How does the US Navy body fat method work?
The US Navy method estimates body fat percentage using circumference measurements of your neck, waist, and hips (for women). These measurements are plugged into a logarithmic formula along with your height to produce an estimate. It is one of the most accessible body fat estimation methods that does not require specialized equipment.
How accurate is the US Navy body fat formula?
The US Navy method is generally accurate within 3 to 4 percent of results from more advanced methods like DEXA scans. It tends to be more reliable for people with average body compositions. For very lean or very overweight individuals, accuracy may decrease somewhat.
What body fat percentage is considered healthy?
Healthy ranges vary by gender. For men, essential fat is around 2 to 5 percent, athletes range from 6 to 13 percent, fitness is 14 to 17 percent, and average is 18 to 24 percent. For women, essential fat is 10 to 13 percent, athletes 14 to 20 percent, fitness 21 to 24 percent, and average is 25 to 31 percent.
Where should I measure my waist and neck?
Measure your waist at the narrowest point of your torso, typically at the navel or just above it. Measure your neck just below the larynx (Adam's apple), with the tape sloping slightly downward to the front. For women, measure hips at the widest point of the buttocks. Use a flexible tape measure and keep it snug but not compressing the skin.
What is lean body mass?
Lean body mass (LBM) is your total body weight minus your fat mass. It includes muscle, bone, organs, water, and other non-fat tissue. Knowing your LBM helps you understand how much of your weight is functional tissue versus stored fat.