Calculate your body fat percentage using the US Navy method. Enter height, neck, waist, and hips. Free online.
BF% (men) = 495 ÷ (1.0324 − 0.19077·log₁₀(W−N) + 0.15456·log₁₀(H)) − 450
BF% (women) = 495 ÷ (1.29579 − 0.35004·log₁₀(W+P−N) + 0.22100·log₁₀(H)) − 450US Navy method: W = waist (cm), N = neck (cm), H = height (cm), P = hips (women only). Uses log₁₀. Measure waist at narrowest point, hips at widest.
This calculator estimates your body fat percentage using the US Navy circumference method — one of the most accessible non-invasive techniques. You only need a tape measure and a few body measurements. No gym equipment or skinfold calipers required.
The formula uses the difference between waist circumference and neck circumference (for men, or waist + hips − neck for women) relative to height. These measurements correlate well with hydrostatic weighing (the gold standard) for most people, with typical accuracy of ±3–4 percentage points. It tends to be less accurate at the extremes — very lean athletes and those with very high body fat.
Use a flexible tape measure pulled snug but not compressing the skin. For waist, measure at the narrowest point — usually just above the navel for men, at the natural waist for women. For hips (women only), measure at the widest point across the buttocks. For neck, measure just below the larynx (Adam's apple), tilting the head slightly forward. Take each measurement twice and average them.
For men, 8–19% is considered healthy (10–25% if considering athletic vs. general fitness). For women, 21–33% is the healthy range. These vary slightly by age.
DEXA scan is the gold standard, but this calculator uses the US Navy method (waist, neck, hip measurements), which is accurate within 3-4% for most people and requires no equipment.
Body Fat Percentage: What It Measures and How to Estimate It