How it works
The US Navy method estimates body fat from height and a few tape measurements: neck and waist for men, plus hips for women. It was developed by the Naval Health Research Center (Hodgdon and Beckett, 1984) and is still used for military fitness screening.
Compared with lab methods like DEXA, the Navy formula is typically within about 3 to 4 percentage points for most people. Measure on bare skin, keep the tape level and snug without compressing, and average two or three readings.
Categories follow the American Council on Exercise (ACE) ranges. Results are estimates, not medical advice.
Formula
Men: %BF = 495 ÷ (1.0324 − 0.19077·log₁₀(waist − neck) + 0.15456·log₁₀(height)) − 450 · Women: 495 ÷ (1.29579 − 0.35004·log₁₀(waist + hip − neck) + 0.22100·log₁₀(height)) − 450 (cm)
Questions people ask
How accurate is the Navy body fat method?
For most adults it lands within roughly 3 to 4 percentage points of DEXA scans. It is less accurate at the extremes, for very lean or very muscular people, and when measurements are taken inconsistently.
Where exactly should I measure?
Neck: just below the Adam's apple, tape angled slightly down at the front. Waist: men at the navel, women at the narrowest point. Hips: the widest part of the buttocks. Measure relaxed, not after a meal.
Why does the calculation differ for women?
Women naturally carry more essential fat and store more on the hips, so the women's equation adds a hip measurement and uses different coefficients.
What is essential fat?
The minimum fat needed for normal body function: about 2–5% for men and 10–13% for women. Going below it is not healthy.