CalculatorsBody and fitnessLean body mass calculator
Lean body mass calculator
Estimate everything in your body that isn't fat: muscle, bone, organs and water. See the equations side by side, and use your body fat if you know it.
50.3kg
- In pounds
- 111 lb
- Boer equation
- 50.3 kgFrom height and weight
- Hume equation
- 49.1 kgFrom height and weight
- The rest, mostly fat
- 21.7 kg30% of your weight
See the working
Boer = 0.252 × 72 + 0.473 × 170 − 48.3 = 50.3 kgThese equations only see height and weight, so they can't tell muscle from fat. They read low if you're very muscular, and can read high if you carry a lot of body fat.
What lean body mass is
It's your weight minus your fat. That's more than muscle, because it also counts bone, organs and water, so it isn't the same as muscle mass.
It matters because it sets much of what you burn at rest, and because it's what you want to hold on to while losing weight. A falling scale can hide a falling lean mass.
Why the equations disagree
Boer and Hume both predict lean mass from height and weight, using measurements from different groups of people, so they land a little apart. Neither can see your actual muscle or fat.
A body fat figure from a DEXA scan is much closer to the truth. A smart scale is rougher and shifts with hydration, though its trend can still be useful.
Questions
Is this the same as muscle mass?
No. Skeletal muscle is usually about half of lean mass. The rest is bone, organs, water and connective tissue.
What's a good lean body mass?
There's no standard target, since it depends so much on your height and frame. Your own trend tells you more than comparing with anyone else.
How do I keep it while losing weight?
Lose slowly, train for strength and eat enough protein. Those three have the best evidence.
How accurate is this?
It's a population estimate, so an individual can be well off. It reads low if you're very muscular, and can read high if you carry a lot of fat.
Sources
- Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. American Journal of Physiology, 1984.
- Hume R. Prediction of lean body mass from height and weight. Journal of Clinical Pathology, 1966.
Written by LifeFrom from the sources above, and not yet reviewed by a clinician. An estimate for your own understanding: it doesn't diagnose or treat anything, and it doesn't replace your doctor.
