What this calculator tells you
Lean body mass includes muscle, bone, organs, and body water—everything except estimated fat mass. It can provide better context than scale weight alone.
How to use the Lean Body Mass Calculator
- 1
Enter body weight and its unit.
- 2
Add a recent body-fat estimate from one consistent method.
- 3
Compare trends over weeks rather than daily changes.
Formula and interpretation
Method
Lean body mass = body weight × (1 − body-fat percentage ÷ 100).
How to read the result
Use the number to track broad body-composition trends or to place protein and strength goals in context.
Important limitations
The result is only as accurate as the body-fat input. Day-to-day hydration changes and measurement-method error can move the estimate.
Lean Body Mass Calculator questions
Is lean body mass the same as muscle mass?
No. Lean mass also includes water, bone, organs, and other non-fat tissue.
Should lean mass change every week?
Usually not in a meaningful way. Small short-term changes are often measurement noise or hydration.
