Lean body mass is everything that isn't fat — muscle, bone, organs and water. The US Navy method estimates body-fat percentage from simple tape measurements, and lean mass is your weight minus that fat. It's quick and needs no special equipment.
Track progress
Measure what matters.
Body tape measure
Consistent measurements.
Smart body scale
Track weight and trends.
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Frequently asked questions
What is the Navy method?
A body-fat formula using height, neck and waist (plus hips for women) — accurate enough for tracking trends without callipers.
What is a healthy body-fat range?
Roughly 10–20% for men and 18–28% for women, though athletes are often lower.