Estimate body fat percentage with the U.S. Navy method.
This calculator uses the US Navy circumference method, developed in the 1980s as a practical field assessment. It estimates body fat from height and a small number of tape measurements — neck and waist for men, plus hips for women — because fat distribution correlates reasonably well with those dimensions.
Its appeal is that it needs nothing but a tape measure. Its limitation is that it infers composition from shape rather than measuring it, so accuracy is typically within three to four percentage points for the general population and worse for very lean or very muscular individuals.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Women carry more essential fat than men for physiological reasons, so the categories are not comparable across the columns. Sustained levels below the essential threshold carry real health consequences, including hormonal disruption.
Because the method is sensitive to tape placement, consistency matters more than precision. Measure at the same time of day, ideally in the morning before eating, with the tape snug but not compressing the skin.
For the waist, men measure at the navel and women at the narrowest point. The neck is measured just below the larynx. A centimetre of variation in waist placement can move the result by more than a percentage point, which is why comparing measurements taken by different people is unreliable.
Track the trend rather than the absolute value. If the method has a systematic bias for your body, that bias stays roughly constant, so the direction of change remains meaningful even when the number is not exact.
DEXA scanning is the practical gold standard and also measures bone density and regional distribution. Hydrostatic weighing and air displacement plethysmography are similarly accurate but less accessible. Skinfold calipers, in trained hands, outperform circumference methods; in untrained hands they do not.
Consumer bioelectrical impedance scales are convenient but highly sensitive to hydration — readings can swing several percentage points depending on how much you have had to drink.