Lean body mass is the weight of everything in your body except fat — muscle, bone, water and organs. This free lean body mass calculator uses the well-known Boer formula to estimate your lean mass and body fat percentage from your sex, height and weight. Please treat the result as a general estimate for information only; it is not medical advice.
This is a general estimate for information only and is not medical advice. For personalised guidance, please speak to a qualified health professional.
How to Use
- Choose your sex.
- Enter your height in centimetres and your weight in kilograms.
- Select “Calculate Lean Mass” to see your estimated lean body mass and body fat percentage.
Key Features
- Based on the recognised Boer formula.
- Shows both lean mass and an estimated body fat percentage.
- Clearly labelled as a general estimate, not medical advice.
- Instant results with no sign-up required.
FAQs
What is lean body mass?
Lean body mass is your total body weight minus body fat. It includes muscle, bone, water, skin and organs.
How accurate is the Boer formula?
It gives a reasonable general estimate for most adults, but individual results vary. It is not a substitute for a clinical body composition measurement.
Why does sex matter in the calculation?
Men and women typically carry different proportions of muscle and fat, so the formula uses different coefficients for each.