PureCalc
Body Composition

Body Fat Calculator

PC

Written byPureCalc Editorial Team

Updated: April 27, 2026 • Verified Clinical Formula

Estimate your total body fat percentage using the highly accurate US Navy Circumference Method. Get a detailed breakdown of your fat mass versus lean body mass.

ft
in
lbs
in
in

Your Body Composition Result

18%
ACE Category: Average / Acceptable
Essential FatFitnessObesity

Lean Body Mass

131.3 lbs

Muscle, bone density, organs, and fluid mass.

Fat Mass

28.7 lbs

Adipose tissue (storage and essential fat) mass.

The US Navy Circumference Method is a highly reliable population estimate with a standard margin of error of 3–4%. Variations can occur for individuals with extreme vascular fluid retention, hypertrophied neck musculature, or asymmetric adipose storage.

Understanding Your Body Fat Percentage

What is Body Fat Percentage?

Your body fat percentage represents the total mass of fat in your body divided by your total body mass, multiplied by 100. This includes both essential body fat (required for structural insulation, neurological support, and hormone regulation) and storage body fat (adipose tissue stored as fuel reserves).

Unlike BMI (Body Mass Index), which only uses height and weight, body fat percentage measures true body composition. This makes it an invaluable metric for bodybuilders, athletes, and individuals on weight loss journeys who want to confirm they are shedding actual fat tissue rather than losing valuable skeletal muscle.

The US Navy Circumference Method

Our calculator uses the mathematical equations developed by the U.S. Navy Health Research Center in the 1980s. Research shows this tape-measurement protocol matches dual-energy X-ray absorptiometry (DEXA) scans with a standard margin of error of just 3% to 4%, making it the most accurate, accessible at-home screening method available.

// Male Formula (Imperial Measurements)
BFP = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76
// Female Formula (Imperial Measurements)
BFP = 163.205 × log10(waist + hips - neck) - 97.684 × log10(height) - 78.387

How to Take Accurate Tape Measurements

To achieve DEXA-like accuracy, measurements must be taken carefully using a flexible, non-stretchable measuring tape. Keep the tape parallel to the floor, flat against the skin, and pulled snug but without depressing the tissue:

  • Height: Measure without shoes, standing straight against a wall with chin tucked parallel to the floor.
  • Neck: Measure just below the larynx (Adam's apple), wrapping the tape slightly sloping downward toward the neck base. Avoid shrugging or flexing the neck.
  • Waist: Measure horizontally. For males, wrap around the navel (belly button). For females, wrap around the narrowest point of the natural waistline (usually halfway between the rib cage and navel).
  • Hips (Females only): Wrap the tape horizontally around the widest part of the gluteus maximus (hips/buttocks).

ACE Body Fat Classifications

The American Council on Exercise (ACE) classifies body fat percentages in adults according to the following ranges:

CategoryMen's RangeWomen's Range
Essential Fat2% - 5%10% - 13%
Athletes6% - 13%14% - 20%
Fitness14% - 17%21% - 24%
Acceptable / Average18% - 24%25% - 31%
Obesity≥ 25%≥ 32%