Lean Mass

Updated August 16, 2025

Lean Mass commonly refers to all non-fat tissues. In many tools it is used interchangeably with fat-free mass.

Notes

Item	Detail
Usage	Some definitions include essential fats in lean mass; most consumer tools do not
Tracking	Use the same device and conditions for consistent trends

Fat-Free Mass is everything in your body that is not fat, including muscle, organs, bone, and water.

Body Fat Percentage is the share of your body that is fat mass.