Muscle Mass Calculator – Lean Body Mass & Body Composition Tracker

The Navy formula uses circumference measurements (neck, waist, and hip) with height to estimate body fat percentage. It's more accurate than BMI for athletic individuals but uses standardized measurements.

The Navy formula is reasonably accurate (within 3-5% of actual body fat) when measurements are precise. For highest accuracy, use DEXA scans or hydrostatic weighing.

Lean mass includes muscle, bones, organs, and water. Muscle mass is just the muscle tissue. This calculator estimates muscle mass from body fat percentage.

Measure once monthly for consistent tracking. More frequent measurements don't show meaningful changes due to water retention and natural fluctuations.

Muscle percentage depends on training, genetics, and body fat. Without resistance training, muscle mass is typically lower. Consistent strength training builds muscle over weeks.

Yes, with proper strength training and adequate protein. This is called body recomposition and works best with beginner lifters or those returning to training.

For men: 35-50% is healthy, 25-35% is average. For women: 25-35% is good, 15-25% is average. Athletic individuals have higher percentages.

Accurate measurements are critical. Measure in the same location consistently, without flexing or pulling the tape too tight. Take measurements at the same time of day.