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Estimate body fat percentage using the U.S. Navy circumference method.
Estimate body fat percentage using the U.S. Navy circumference method.
Enter values above and click Calculate — results will appear here with the formula explained.
The U.S. Navy tape method estimates fat percentage from where bodies store it: waist relative to neck for men, adding hips for women, scaled by height. It costs nothing and repeats easily, making it practical for tracking direction even if absolute precision is limited. The military adopted it precisely because calipers and dunk tanks don't scale to thousands of recruits — a tape and a formula do.
Accuracy depends on technique — same anatomical landmarks each time, relaxed muscles, snug-but-not-compressing tape. Measure waist at the navel (not the narrowest point), neck below the larynx, hips at the widest point for women. Expect ±3–4 points of spread versus DEXA scans; trend changes matter more than the raw number itself. Two readings a month apart with identical technique beat one 'precise' reading from inconsistent landmarks.
Method hierarchy by accuracy and cost: DEXA scans (±1–2%, expensive, low radiation) top the practical list, followed by hydrostatic weighing and BodPod (±2–3%, facility-bound), then multi-site skinfold calipers in skilled hands (±3–4%), the Navy tape method (±3–4% with good technique), and bioelectrical impedance scales (±5–8%, wildly hydration-dependent). Smart scales that swing 5 points day-to-day aren't broken — they're measuring water, meals and glycogen as much as fat.
Healthy ranges are sex- and age-dependent in ways single numbers hide: essential fat alone is ~3–5% for men versus ~10–13% for women, athletes run ~6–13% / ~14–20%, general fitness ~14–17% / ~21–24%, and average populations higher still. Ranges drift upward with age as muscle yields to fat at stable weight — the same scale number at 25 and 55 can mean 5+ points more fat. Judge against the band for your sex and decade, not a magazine cover.
Body fat beats BMI and scale weight as the actionable metric because it separates what to lose (fat) from what to keep (muscle). Recomposition — same weight, less fat, more muscle — is invisible to BMI and the scale but obvious here: waist shrinking while weight holds steady is the signature. Pair this estimate with strength progression and waist trend for the complete picture; any one metric alone misleads.
For health interpretation, distribution rivals total: visceral abdominal fat drives metabolic risk far more than subcutaneous fat at the same percentage, which is why waist circumference and waist-to-height ratio (<0.5) deserve equal billing. A 'healthy' 22% with a 0.58 waist-to-height ratio warrants more attention than 25% carried peripherally. Discuss personal results with a clinician — estimates inform, they don't diagnose.
Estimate body fat percentage using the U.S. Navy circumference method. Formula: Navy method uses log₁₀ of circumference ratios: men: 86.01·log₁₀(waist−neck) − 70.041·log₁₀(height) + 36.76. Example: A male at 180 cm with 38 cm neck and 85 cm waist: 86.01·log₁₀(47) − 70.041·log₁₀(180) + 36.76 ≈ 17.5% estimated body fat.
The U.S. Navy tape method estimates fat percentage from where bodies store it: waist relative to neck for men, adding hips for women, scaled by height. It costs nothing and repeats easily, making it practical for tracking direction even if absolute precision is limited. The military adopted it precisely because calipers and dunk tanks don't scale to thousands of recruits — a tape and a formula do.
Accuracy depends on technique — same anatomical landmarks each time, relaxed muscles, snug-but-not-compressing tape. Measure waist at the navel (not the narrowest point), neck below the larynx, hips at the widest point for women. Expect ±3–4 points of spread versus DEXA scans; trend changes matter more than the raw number itself. Two readings a month apart with identical technique beat one 'precise' reading from inconsistent landmarks.
Method hierarchy by accuracy and cost: DEXA scans (±1–2%, expensive, low radiation) top the practical list, followed by hydrostatic weighing and BodPod (±2–3%, facility-bound), then multi-site skinfold calipers in skilled hands (±3–4%), the Navy tape method (±3–4% with good technique), and bioelectrical impedance scales (±5–8%, wildly hydration-dependent). Smart scales that swing 5 points day-to-day aren't broken — they're measuring water, meals and glycogen as much as fat.
Healthy ranges are sex- and age-dependent in ways single numbers hide: essential fat alone is ~3–5% for men versus ~10–13% for women, athletes run ~6–13% / ~14–20%, general fitness ~14–17% / ~21–24%, and average populations higher still. Ranges drift upward with age as muscle yields to fat at stable weight — the same scale number at 25 and 55 can mean 5+ points more fat. Judge against the band for your sex and decade, not a magazine cover.
Body fat beats BMI and scale weight as the actionable metric because it separates what to lose (fat) from what to keep (muscle). Recomposition — same weight, less fat, more muscle — is invisible to BMI and the scale but obvious here: waist shrinking while weight holds steady is the signature. Pair this estimate with strength progression and waist trend for the complete picture; any one metric alone misleads.
For health interpretation, distribution rivals total: visceral abdominal fat drives metabolic risk far more than subcutaneous fat at the same percentage, which is why waist circumference and waist-to-height ratio (<0.5) deserve equal billing. A 'healthy' 22% with a 0.58 waist-to-height ratio warrants more attention than 25% carried peripherally. Discuss personal results with a clinician — estimates inform, they don't diagnose.
A male at 180 cm with 38 cm neck and 85 cm waist: 86.01·log₁₀(47) − 70.041·log₁₀(180) + 36.76 ≈ 17.5% estimated body fat. A recomposition case: same man three months later at identical weight but 82 cm waist re-measures near 15.5% — two points of fat exchanged for muscle, invisible to BMI and the bathroom scale.
Formulas are standard public references (see our methodology). External standards are cited in the text where they apply.
Last reviewed: September 2026 · Report an error