What is the Lean Body Mass Calculator?
Lean body mass is everything in your body except fat: muscle, bone, organs and water. This calculator estimates it from your weight and height.
How to use the Lean Body Mass tool
- Enter Sex, Weight and Height.
- The result updates instantly as you type, or press Calculate.
- Use Try an example to see how it works, and Reset to start again.
Formula
Boer formula, men: 0.407 × weight + 0.267 × height − 19.2. Women: 0.252 × weight + 0.473 × height − 48.3.
Worked example
With sex Male, weight 75 kg, height 175 cm, the lean body mass comes to 58.1 kg. Fat mass: 17 kg; Body fat: 22.6%.
Frequently asked questions
Why track lean body mass?
It shows whether weight change comes from fat or muscle, which matters more than the scale alone.
Is the Boer formula exact?
It is an estimate. Body scans give more precise measurements.
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Checked by Calcovate · Formula tested against worked examples · Updated 7 Nov 2026 · How we check our calculators. General information only, not financial or medical advice.