Body Fat %
Estimated fat proportion.
What does Body Fat % mean?
Body fat percentage is the proportion of your total body weight that is fat tissue. It is a more meaningful indicator of fitness and health than weight alone, because it distinguishes between fat mass and lean mass (muscle, bone, organs, water). Healthy ranges vary by sex and age: typically 10–20% for men and 18–28% for women. Very low body fat can impair hormonal function, while excess body fat increases the risk of cardiovascular disease, diabetes, and other conditions.
How to calculate Body Fat %
This calculator uses the U.S. Navy circumference method. For men: Body Fat % = 495 / (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. For women: Body Fat % = 495 / (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450. All measurements are in centimeters. Fat mass and lean mass are then derived from your total weight: Fat Mass = Weight × Body Fat % / 100, and Lean Mass = Weight − Fat Mass.
FAQ
The US Navy method is considered reasonably accurate for most adults, typically within 3–4% of results from more advanced methods like DEXA scans. Accuracy improves when measurements are taken consistently at the same body landmarks. It may be less accurate for very lean or very obese individuals.
Waist: measure horizontally at the navel (belly button) level. Neck: measure just below the larynx (Adam's apple), keeping the tape level. Hip (women only): measure at the widest point of the buttocks. Keep the tape snug but not compressing the skin, and measure on bare skin when possible.
For men, essential fat is about 2–5% and a healthy athletic range is 6–13%, while a fit range is 14–17% and average is 18–24%. For women, essential fat is 10–13%, athletic is 14–20%, fit is 21–24%, and average is 25–31%. Values above these ranges are generally considered excess body fat.
Men and women store fat differently. Women naturally carry more essential fat (for reproductive function and hormone regulation) and tend to store fat around the hips and thighs, while men store more fat around the abdomen. The female formula includes a hip measurement to account for this difference in fat distribution.
BMI is a simple ratio of weight to height and does not distinguish between fat and muscle. A muscular person may have a high BMI but low body fat. Body fat percentage directly estimates the proportion of fat tissue, making it a more accurate indicator of body composition and health risk.
Related calculators
- BMI— Body mass index estimate.
- BMR— Basal metabolic rate.
- Calorie Needs (TDEE)— Total daily energy expenditure.
- Heart Rate Zone— Target exercise range.