Health & Wellness

Lean body mass (LBM)

Estimate your lean and fat mass from sex, height and weight.

  • Instant
  • Free
  • Private (processed locally)
  • No sign-up

ℹ️ Estimate via the Boer formula. Lean mass includes muscle, bone, organs and water. Indicative; not a substitute for a clinical measurement.

Estimate your body composition

Pick the sex, enter height and weight: the tool estimates your lean body mass, fat mass and body fat percentage, with a split bar.

  1. Sex

    Male or female.

  2. Height and weight

    In cm and kg.

  3. Read the result

    Lean + fat mass.

Boer formula

  • Male: 0.407 × weight + 0.267 × height − 19.2
  • Female: 0.252 × weight + 0.473 × height − 48.3
  • Fat mass = weight − lean mass
  • Weight in kg, height in cm

Example: male, 175 cm, 75 kg

ItemValue
Lean body mass58.1 kg
Fat mass16.9 kg
Body fat22.6%

Estimate via the Boer formula, for educational purposes. For a precise measurement, consult a professional.

Frequently asked questions

What is lean body mass?

It is everything that is not fat: muscle, bone, organs, body water. It is also called fat-free mass (FFM).

Which formula is used?

The Boer formula (1984). Male: 0.407 × weight + 0.267 × height − 19.2. Female: 0.252 × weight + 0.473 × height − 48.3 (weight in kg, height in cm).

What is the number for?

To track body composition, estimate protein needs or lean-mass-based dosing. It is an estimate, not an exact measurement.

Is this medical advice?

No. For a precise measurement (DEXA, bioimpedance), consult a professional.