What is Body Fat Percentage?
Body fat percentage is the total mass of fat divided by total body mass, multiplied by 100. It includes both essential fat (necessary for life and reproductive functions) and storage fat (accumulated in adipose tissue). Unlike BMI, body fat percentage directly measures fat mass and provides a more accurate picture of body composition.
Calculation Methods
US Navy Method
The US Navy method uses circumference measurements to estimate body fat. It is considered more accurate than BMI-based estimates because it accounts for body shape differences. The formula uses height, waist, neck (and hip for women) measurements.
- Men: %BF = 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
- Women: %BF = 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450
BMI Method
The BMI-based method estimates body fat from your Body Mass Index. While less accurate, it only requires height and weight measurements. The formula adjusts for gender differences in fat distribution.
Body Fat Categories
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obese | 25%+ | 32%+ |
How to Take Measurements
- Waist: Measure at the narrowest point, or at the navel for men
- Neck: Measure just below the larynx (Adam's apple)
- Hip (women): Measure at the widest point of the buttocks