Estimated lean body mass (Boer, James, Hume)
Lean mass is everything that is not fat: muscle, bone, organs, water. Enter sex, height and weight: the tool compares three published formulas.
General information, not medical advice. This result does not replace a doctor. If in doubt or if you have symptoms, see a health professional.
Result
61.4Estimated lean body mass (kg)
- Remaining share of weight, by this formula
- 23.2%
- Boer formula (kg)
- 61.4
- James formula (kg)
- 62.7
- Hume formula (kg)
- 57.8
Inputs
- Sex (for the formula)
- Man
- Height
- 180
- Weight
- 80
- Main formula
- Boer (1984)
How it is calculated
Boer: man 0.407 × weight + 0.267 × height − 19.2; woman 0.252 × weight + 0.473 × height − 48.3.
Result
Estimated lean body mass (kg)
- Remaining share of weight, by this formula
- 23.2%
- Boer formula (kg)
- 61.4
- James formula (kg)
- 62.7
How it is calculated
- Boer: man 0.407 × weight + 0.267 × height − 19.2; woman 0.252 × weight + 0.473 × height − 48.3.
- James: man 1.1 × weight − 128 × (weight ÷ height)²; woman 1.07 × weight − 148 × (weight ÷ height)².
- Hume: man 0.32810 × weight + 0.33929 × height − 29.5336; woman 0.29569 × weight + 0.41813 × height − 43.2933.
- Weight in kg, height in cm. Remaining share = 100 − lean mass ÷ weight × 100.
Example
Man, 180 cm, 80 kg: Boer 61.4 kg, James 62.7 kg, Hume 57.8 kg. Remaining share by Boer: 23.2%.
Good to know
- These are population formulas: the gap with a real measurement can be several kilos.
- They do not suit children, pregnancy, very muscular people or very high BMI.
- A reliable measurement needs a test (for example DEXA) ordered by a professional.
Sources
- Boer P., Am J Physiol, 1984
- James W.P.T., Research on obesity, HMSO, 1976
- Hume R., J Clin Pathol, 1966
When to use it
- Compare published lean-mass estimates for adults using three named formulas.
- See how Boer, James and Hume differ for the same height and weight.
- Ask a qualified professional about body-composition testing instead of treating an estimate as a diagnosis.
Frequently asked questions
What does lean body mass mean?
It estimates body weight excluding fat and includes muscle, bone, organs and water.
Why do the three formulas give different results?
They use different equations and study populations. Their results are estimates, not a direct measurement of body composition.
Can I use this result to assess my health?
No. It is a mathematical estimate, not a medical test. These formulas are not intended for children, pregnancy or some body types.