Lean Body Mass Calculator
Everything that isn't fat: muscle, bone, organs and water.
Enter your values
ⓘ Live results
Results
- Lean body mass
- 130 lb
- Fat mass
- 40 lb
- Body fat
- 23.5%
- Fat-free mass index
- 19.2
Quick answer
Lean body mass is total weight minus fat mass; the Boer formula estimates it from height and weight alone.
Male LBM = 0.407·kg + 0.267·cm − 19.2
How to use the Lean Body Mass Calculator
- 1Choose your units.
- 2Enter weight, height and sex.
- 3Read lean mass and estimated fat mass.
Worked example
Using the values the calculator loads with:
Inputs
- UnitsImperial (lb, in)
- Weight170
- Height69
- SexMale
Results
- Lean body mass130 lb
- Fat mass40 lb
- Body fat23.5%
- Fat-free mass index19.2
Frequently asked questions
Why track lean mass?
During a diet it shows whether you are losing fat or muscle, which weight alone cannot tell you.
What is a good FFMI?
Around 19–21 for trained men and 15–17 for trained women; above 25 without drugs is very rare.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.