How to use this calculator
- Enter or choose sex.
- Enter or choose units.
- Enter or choose body fat (optional).
- The lean body mass (Boer) updates as you type. Use Copy result or Share to keep it.
Method
Boer: men 0.407W + 0.267H − 19.2, women 0.252W + 0.473H − 48.3; Hume: men 0.32810W + 0.33929H − 29.5336, women 0.29569W + 0.41813H − 43.2933; From body fat: W × (1 − BF%)
- W
- weight in kg
- H
- height in cm
- BF%
- measured body fat percentage
Worked example
- Boer: 0.407 × 80 + 0.267 × 180 − 19.2 = 32.56 + 48.06 − 19.2 = 61.4 kg.
- Hume: 0.3281 × 80 + 0.33929 × 180 − 29.5336 = 26.25 + 61.07 − 29.53 = 57.8 kg.
- Lean share (Boer) = 61.42 ÷ 80 = 76.8%, implying 18.6 kg of fat.
A man 180 cm tall weighing 80 kg has an estimated lean body mass of about 61.4 kg (Boer) or 57.8 kg (Hume).
What the result means
The two equations differ by a few kilograms, which shows the uncertainty of height-and-weight estimates. Lean body mass is used to scale protein targets, to dose some medicines and contrast agents, and to follow changes in muscle during training or weight loss.
Assumptions and limits
- Adult equations; Boer (1984) and Hume (1966) were derived in adult populations.
- Weight in kg and height in cm (US inputs are converted).
- Height-and-weight equations cannot tell a muscular person from a person with more fat at the same size.
- Accuracy falls in obesity, in older adults and in children.
Questions
Is lean body mass the same as muscle mass?
No. It includes bone, organs, skin and body water as well as muscle, so it is always larger than muscle mass alone.
Which result should I use?
If you have a reliable body fat measurement, the body-fat method is the most direct. Otherwise Boer is the equation most often used clinically.
Sources
Please note: This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health.