Body Fat Percentage Calculator (Navy Method)
Estimate your body fat percentage using only a tape measure and the U.S. Navy circumference method. Ideal for anyone who wants a quick, equipment-free body composition check.
About this calculator
The U.S. Navy method estimates body fat from body circumferences rather than skinfold calipers or DEXA scans. For men, the formula is: %BF = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450. For women: %BF = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hips − neck) + 0.22100 × log₁₀(height)) − 450. All measurements are in inches. The logarithmic terms capture the non-linear relationship between girth differences and fat mass. While not as precise as hydrostatic weighing, the Navy method correlates well with laboratory methods and carries a typical error of ±3–4 percentage points. Measurements should be taken at the same time of day for consistent tracking.
How to use
Example: a male with height 70 in, waist 34 in, and neck 15 in. Step 1 — waist − neck = 34 − 15 = 19. Step 2 — log₁₀(19) ≈ 1.2788; log₁₀(70) ≈ 1.8451. Step 3 — denominator: 1.0324 − (0.19077 × 1.2788) + (0.15456 × 1.8451) = 1.0324 − 0.2440 + 0.2851 = 1.0735. Step 4 — %BF = (495 ÷ 1.0735) − 450 = 461.1 − 450 = 11.1%. This result places the individual in the fitness category for males according to ACE body fat standards.
Frequently asked questions
How accurate is the Navy method for measuring body fat percentage compared to DEXA?
The U.S. Navy circumference method typically agrees with DEXA scan results within ±3–4 percentage points for most adults. It consistently performs better than BMI for estimating fatness and is more practical than skinfold calipers for self-measurement. However, it can underestimate body fat in very muscular individuals and overestimate it in people with unusual fat distribution patterns. For clinical precision, methods like hydrostatic weighing or DEXA remain the gold standard.
Where exactly should I measure my waist for the Navy body fat formula?
For the Navy method, waist circumference is measured at the navel (belly button) level, not at the narrowest point of the torso. This differs from some other health guidelines that use the natural waist. Measurement should be taken at the end of a normal exhale, with the tape parallel to the floor and snug but not compressing the skin. Consistent measurement location is critical — a 1-inch error can shift results by 1–2 percentage points.
What is a healthy body fat percentage range for men and women?
According to the American Council on Exercise, essential fat is 2–5% for men and 10–13% for women. Athletes typically range 6–13% (men) and 14–20% (women). Fitness-level body fat is 14–17% for men and 21–24% for women, while acceptable ranges extend to 24% and 31% respectively. Above these thresholds is classified as obese. These ranges vary slightly by age, and older adults naturally carry a higher percentage of fat at the same body weight.