Lean body mass calculator
Lean body mass is everything that isn’t fat. Tracking it tells you whether a diet is costing you muscle.
Calculated in your browser. Nothing you enter is sent anywhere.
Formulas
Boer (1984): men 0.407 × weight (kg) + 0.267 × height (cm) − 19.2; women 0.252 × weight + 0.473 × height − 48.3. With a body fat reading, lean mass = weight × (1 − body fat %).
To track lean mass over time, use the same body fat method every time, and see what changed with the fat vs muscle loss calculator.
FAQ
Frequently asked questions
What is a normal lean body mass?
Typically about 75–85% of bodyweight for men and 65–75% for women, depending on body fat.
Is lean body mass the same as muscle?
No. It includes muscle, bone, organs, skin and water. Muscle is roughly half of it.