The U.S. Navy body fat formula estimates body fat percentage from neck, waist, and hip (women) circumferences plus height. It is a field method—not as precise as DEXA—but useful for tracking trends when measured consistently.
Measure at the same time of day, tape snug but not compressing skin. Navy method error can be several percentage points. For screening only—not diagnosis. Compare with BMI as complementary data.
Related tools & guides
Body composition shifts slowly. Pair measurements with Strength Training for Beginners and adequate protein from How Much Protein Do You Need Per Day?