Lean body mass calculator
Lean body mass is everything except fat: muscle, bone, organs and water. With a body fat estimate it follows directly; without one, formulas based on height and weight give a reasonable estimate.
From the body fat calculator, a smart scale or a DEXA scan.
From your body fat
65.6 kg
Fat mass
14.4 kg
Boer formula
60.9 kg
James formula
62.1 kg
Hume formula
57.1 kg
Which estimate is best?
If you know your body fat, lean mass = weight × (1 − body fat) is the most direct estimate, and it is as accurate as the body fat measurement.
Without body fat, the Boer formula is generally the most accurate of the three for adults. The James formula underestimates lean mass at high body weight (it even starts to decrease above a certain weight), so use it with caution in obesity.
Why lean body mass matters
It is used to set protein and calorie targets, to dose some medicines, and to check whether weight loss comes from fat or from muscle.
Sources
- Boer P (1984). Estimated lean body mass as an index for normalization of body fluid volumes in humans. American Journal of Physiology 247:F632–F636.
- James WPT (1976). Research on obesity. London: Her Majesty's Stationery Office.
- Hume R (1966). Prediction of lean body mass from height and weight. Journal of Clinical Pathology 19:389–391.