The Body Fat Percentage Calculator estimates the proportion of your body weight that is fat mass using body measurements. Unlike BMI, it distinguishes between fat and lean mass — giving a clearer picture of body composition and health risk.
Body Fat Percentage Calculator
Estimate your body fat percentage using the U.S. Navy method.
How to Use This Calculator
- Select your gender — men and women store fat differently, so separate formulas apply.
- Enter your weight, height, and key circumference measurements (waist, neck, and for women, hip).
- Click Calculate.
Body Fat Percentage Categories
| Category | Women | Men |
|---|---|---|
| Essential Fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32%+ | 25%+ |
Why Body Fat % Is More Informative Than BMI
BMI only measures weight relative to height — it cannot distinguish between muscle and fat. A muscular athlete may have a BMI classified as “overweight” while having very low body fat. Conversely, a sedentary person with a normal BMI may have excess fat (“skinny fat”) with associated health risks.
Body fat percentage, combined with waist circumference, gives a far better picture of metabolic health risk. Research consistently shows that abdominal (visceral) fat — not total weight — is the strongest predictor of cardiovascular disease and type 2 diabetes.
How to Measure Accurately
- Waist: Measure at the narrowest point, about 1 inch above the belly button. Don’t suck in.
- Neck: Measure just below the larynx (Adam’s apple), sloping slightly downward at the front.
- Hip (women only): Measure at the widest point of the buttocks.
- Measure in the morning before eating, using a flexible tape measure.
Frequently Asked Questions
How accurate is this measurement method?
The US Navy circumference method used here is within 3–4% accuracy for most people — comparable to skinfold calipers. DEXA scans and hydrostatic weighing are more accurate (±1–2%) but require specialized equipment. For tracking progress over time, consistency of measurement technique matters more than absolute accuracy.
What body fat percentage should I aim for?
For health and longevity, the fitness range (14–20% for women, 14–17% for men) is ideal for most people. Achieving athlete-level body fat requires significant dietary restriction and is not necessary for good health.
How it works
The US Navy method uses circumference measurements to estimate body fat. For men: body density is calculated from neck and waist measurements relative to height, then converted to body fat % using the Siri equation. For women, the hip measurement is added. The formula was developed through research on military personnel.Formula
Men: BF% = 86.010×log10(waist−neck) − 70.041×log10(height) + 36.76. Women: BF% = 163.205×log10(waist+hip−neck) − 97.684×log10(height) − 78.387