What is body fat percentage?
Body fat percentage is the proportion of your total body weight that consists of fat tissue. Unlike BMI, which only considers height and weight, body fat percentage distinguishes between fat mass and lean mass (muscle, bone, water, organs). This makes it a more accurate indicator of body composition and overall health risk. Men typically carry less essential fat (2–5%) than women (10–13%) due to biological differences in reproductive function and hormone levels.
How do you calculate body fat percentage?
This calculator offers two proven methods. The U.S. Navy method uses circumference measurements — height, neck, and waist for men, plus hips for women — and applies a logarithmic formula to estimate body density. The Jackson-Pollock 3-site skinfold method uses caliper measurements at three body sites: chest, abdomen, and thigh for men; triceps, suprailiac, and thigh for women. Both methods convert body density to body fat percentage using the Siri equation. If you also enter your weight, the calculator shows your fat mass and lean mass in kilograms.
What is the U.S. Navy body fat formula?
The Navy method (Hodgdon & Beckett, 1984) estimates body density from circumference measurements in centimeters. For men: %BF = 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450. For women: %BF = 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450. This method has an accuracy of approximately ±3.5% when measurements are taken correctly.
What are healthy body fat percentage ranges?
Body fat categories differ by sex. For men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25%+. For women: essential fat 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, obese 32%+. These ranges reflect the fact that women naturally carry more body fat for reproductive and hormonal functions. You can track changes over time alongside your daily energy expenditure to manage body composition.
What are some body fat percentage examples?
A 180 cm tall man with a 38 cm neck and 85 cm waist has approximately 16% body fat using the Navy method, placing him in the fitness category. A 165 cm woman with a 33 cm neck, 70 cm waist, and 95 cm hips has approximately 25% body fat, within the average range. Using skinfold measurements, a 30-year-old man with chest (15 mm), abdomen (20 mm), and thigh (12 mm) folds totaling 47 mm has roughly 14% body fat.
Is body fat percentage more accurate than BMI?
Body fat percentage is generally a better health indicator than BMI because it directly measures fat tissue rather than total weight. BMI can misclassify muscular individuals as overweight and may miss those with high body fat but normal weight — a condition called "skinny fat." Research shows body fat percentage is a stronger predictor of cardiovascular disease risk and metabolic disorders. However, at-home measurement methods have a ±3–4% margin of error, so tracking trends over time is more useful than fixating on a single reading. For a complete picture, combine body fat data with your calorie needs and activity levels.