Lean Body Mass Calculator

Lean body mass (LBM) is your total body weight minus fat mass — muscle, bone, organs, and water. This uses the Boer formula, a widely cited estimate that only needs height and weight.

Lean Body Mass Calculator

Live

Sex

Height (cm)

Weight (kg)

Lean body mass

61.4 kg

Estimated fat mass

18.6 kg

Fat % (approx.)

23.2%

A formula-based estimate — DEXA scans and other body-composition tests are more precise.

The Boer formula

Men: LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2 Women: LBM = 0.252 × weight(kg) + 0.473 × height(cm) − 48.3

Example

A man at 80 kg, 180 cm: LBM = 0.407(80) + 0.267(180) − 19.2 ≈ 61.4 kg, leaving about 18.6 kg estimated fat mass (23.2%).

Step-by-step guide

1. Select your sex, height, and weight.
2. Read your estimated lean body mass and implied fat mass.
3. Compare over time rather than focusing on a single reading — trends are more meaningful than one snapshot.

Common mistakes

Treating the formula-based fat mass as clinically precise — it's derived indirectly and can differ from direct measurement methods like DEXA scans.

Confusing this with our Body Fat Calculator, which uses tape measurements directly rather than a height/weight formula — the two can give slightly different fat estimates.

Frequently asked questions

How is this different from the Body Fat Calculator?

This formula estimates lean mass from height and weight alone. Our Body Fat Calculator uses tape measurements (neck, waist, and for women, hips), which typically gives a more individualized estimate since it accounts for your actual body shape.

Why does lean body mass matter?

It's often used as a reference point for setting protein intake targets or tracking training progress, since it reflects the metabolically active tissue on your body rather than total weight alone.

Can lean body mass increase?

Yes — resistance training combined with adequate protein intake is commonly associated with maintaining or building lean mass over time. A doctor or trainer can advise on an approach suited to you.

Related calculators

See more in the Health Calculators section, or try the Body Fat Calculator and Protein Intake Calculator.