Lean Body Mass Calculator
Estimate lean body mass from weight and body-fat percentage.
Enter your details and calculate.
Legion Whey+
Lean mass is the part worth protecting in a deficit, and protein intake is the lever with the most evidence behind it. Whey+ is 22 g per serving, isolate rather than concentrate, third-party tested.
Legion is the only supplement brand this site earns a commission from, and it is said on every page that links to them.
Set your protein target from that lean mass figure
The printable chart: 30+ foods ranked by protein per 100 calories. Lean mass is the number your target should be built on.
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Lean Mass Building Stack
Protein and creatine — the two supplements with the strongest evidence for building lean body mass.
FAQs
What exactly is lean body mass?
Lean body mass (LBM) is everything that isn't fat: muscle, bone, organs and water. It's the number behind smarter dosing — protein and creatine targets scale better with LBM than with total bodyweight, especially at higher body-fat levels.
Why should I track LBM instead of just bodyweight?
Because the scale can't tell muscle from fat. During recomposition (building muscle while losing fat), bodyweight can stay flat while LBM rises — tracking LBM shows real progress the scale hides.
How accurate are LBM formulas?
Equations like Boer estimate LBM from height and weight with reasonable population-level accuracy but can miss individual variation. DEXA scans are the practical gold standard; if you use formula estimates, apply them consistently and watch the trend.