Estimate your body fat percentage using the U.S. Navy circumference method — just a tape measure needed.
The U.S. Navy method estimates body fat from circumference measurements using a logarithmic formula, and is a widely used field method that doesn't require calipers or special equipment.
The Navy method is reasonably accurate for most people (typically within a few percentage points of DEXA scan results) but can be less reliable for people with very high or very low body fat, or unusual body proportions.
It's generally accurate within a few percentage points for most people, making it a solid free alternative to calipers or scans, though not as precise as DEXA or hydrostatic testing.
Body fat distribution patterns differ by sex, so the formula includes hip measurement for women to account for typical fat distribution differences.