Lean Body Mass Calculator
See how much of your body is lean tissue versus fat, using the trusted Boer formula.
Body CompositionScience-backed formula
Enter your details
Fill in the fields, then calculate
Enter your age.
Enter your height.
Enter your weight.
Awaiting Data
Enter your details and tap Calculate to see your results appear here.
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ResultYour result appears here.
What Lean Body Mass Means
Lean body mass is everything in your body that is not fat. Muscle, bone, organs, and water all count. It drives your strength and your resting calorie burn.
Your measurements become one clear number you can track over time.
The Boer formula estimates it from your height, weight, and sex. Subtract it from your weight and you get fat mass.
Tracking lean mass helps you tell muscle gain from fat gain.
How to Use This Calculator
- Enter your sex, age, height, and weight.
- Tap Calculate for lean and fat mass.
The Formula Used
Men: LBM = 0.407·weight(kg) + 0.267·height(cm) − 19.2
Women: LBM = 0.252·weight(kg) + 0.473·height(cm) − 48.3
Women: LBM = 0.252·weight(kg) + 0.473·height(cm) − 48.3
- weight
- Body weight in kilograms.
- height
- Standing height in centimetres.
Understanding Your Results
Higher lean mass
More muscle and bone
Supports strength and metabolism.
Typical
Varies by frame
Depends on height, sex, and training.
Lower lean mass
Less muscle
Strength work can build it up.
Tips to Improve
- Lift weights to grow lean mass.
- Eat enough protein to support muscle.
- Track lean mass alongside scale weight.
- Avoid steep calorie cuts that burn muscle.
Frequently Asked Questions
It tells real progress apart from water and fat changes on the scale.
It estimates well for most adults, though body scans measure it directly.
Strength training plus enough protein and calories builds it steadily.
Scientific References
- Boer, P. (1984). Estimated lean body mass as an index for normalization. American Journal of Physiology, 247(4), F632–F636.
- Hume, R. (1966). Prediction of lean body mass from height and weight. Journal of Clinical Pathology, 19(4), 389–391.
- Janmahasatian, S., et al. (2005). Quantification of lean bodyweight. Clinical Pharmacokinetics, 44(10), 1051–1065.