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Body Fat Percentage Formulas:
Navy Method (men):
%BF = 495 / (1.0324 - 0.19077 * log10(waist - neck) + 0.15456 * log10(height)) - 450
Navy Method (women):
%BF = 495 / (1.29579 - 0.35004 * log10(waist + hip - neck) + 0.22100 * log10(height)) - 450
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Body fat percentage is the proportion of fat to total body weight. Unlike BMI, it directly measures body composition and distinguishes between fat mass and lean mass.
The calculator uses the U.S. Navy body fat formula:
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
Where measurements are in centimeters.
Details: Body fat percentage provides a more accurate health assessment than BMI alone, helping identify risks for obesity-related diseases and tracking fitness progress.
Tips: Measure circumference at:
- Neck: Below the larynx, tape sloping slightly downward
- Waist: At the narrowest point for men, at the navel for women
- Hip (women only): Maximum extension of the buttocks
Q1: How accurate is the Navy method?
A: It's reasonably accurate (±3%) for most people but may underestimate in very lean individuals and overestimate in very obese individuals.
Q2: What are healthy body fat ranges?
A: For men: 8-19% (athletes), 11-21% (fitness), 18-25% (acceptable). For women: 21-33% (athletes), 23-33% (fitness), 25-38% (acceptable).
Q3: When should measurements be taken?
A: Morning before eating, after using the bathroom. Avoid measuring after exercise or when dehydrated.
Q4: Are there other measurement methods?
A: More accurate methods include DEXA scans, hydrostatic weighing, and BodPod, but these require special equipment.
Q5: How often should I measure?
A: Every 4-8 weeks is sufficient to track changes. Daily measurements aren't recommended due to normal fluctuations.