Estimate your body fat percentage from a few tape-measure readings.
This calculator uses the circumference-based formula developed by Hodgdon & Beckett (1984) for the U.S. Navy, using measurements in inches:
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
A 2022 study of physically fit U.S. Marines found that this method underestimated body fat by about 2.5-2.6 percentage points in men and overestimated it by about 1.3-2.3 percentage points in women, with individual variability of roughly 3.7-4.8 percentage points (Potter et al., 2022). Treat the result as a field estimate rather than a research-grade measurement.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Acceptable | 18-24% | 25-31% |
| Above Average | 25%+ | 32%+ |
These are commonly cited fitness-industry categories, not strict medical thresholds — individual healthy ranges vary.
BMI only compares your height to your total weight and can't distinguish muscle from fat. A muscular person can register as "overweight" on the BMI scale while carrying a low body fat percentage. Body fat percentage estimates actual composition, making it more useful for athletes and lifters with above-average muscle mass.
A 2022 study found the method underestimated body fat by about 2.5-2.6 percentage points in men and overestimated it by about 1.3-2.3 percentage points in women, with individual variability around 3.7-4.8 percentage points — a field estimate, not a lab-precise measurement.
Commonly cited fitness ranges are roughly 14-17% for men and 21-24% for women, though this varies by individual and source.
BMI can't distinguish muscle from fat; body fat percentage estimates actual composition directly.
Neck below the larynx; waist at the navel (men) or narrowest point (women); hips at the widest point (women only).
Note: This calculator provides a general estimate for healthy adults, not a medical diagnosis. Body composition assessment tools like DEXA or hydrostatic weighing are more precise if you need clinical accuracy.