Lean Body Mass (Boer Formula) Formula

Understand the math behind the lean body mass (boer formula). Each variable explained with a worked example.

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Formulas Used

Lean Body Mass

lbm_kg = 0.407 * weight_kg + 0.267 * height_cm - 19.2

Lean Body Mass

lbm_lbs = (0.407 * weight_kg + 0.267 * height_cm - 19.2) * 2.20462

Estimated Body Fat

est_body_fat_pct = (1 - (0.407 * weight_kg + 0.267 * height_cm - 19.2) / weight_kg) * 100

Variables

VariableDescriptionDefault
weight_lbsBody Weight(lbs)180
height_inchesHeight(inches)70
weight_kgDerived value= weight_lbs * 0.453592calculated
height_cmDerived value= height_inches * 2.54calculated

How It Works

Boer Formula for Lean Body Mass (Male)

LBM (kg) = 0.407 x Weight(kg) + 0.267 x Height(cm) - 19.2

The Boer formula estimates lean body mass directly from height and weight without requiring a body fat measurement. It is considered one of the more accurate predictive LBM equations.

Worked Example

A 180 lb, 70-inch tall male.

weight_lbs = 180height_inches = 70
  1. 01Weight = 81.6 kg, Height = 177.8 cm
  2. 02LBM = 0.407 x 81.6 + 0.267 x 177.8 - 19.2
  3. 03= 33.2 + 47.5 - 19.2 = 61.5 kg (135.6 lbs)
  4. 04Est body fat = (1 - 61.5 / 81.6) x 100 = 24.6%

Frequently Asked Questions

What is the Boer formula?

The Boer formula (1984) estimates lean body mass from height and weight. It has separate equations for males and females and is widely used in clinical settings.

How does this differ from the simple LBM formula?

The simple method requires knowing body fat percentage. The Boer formula estimates LBM directly from height and weight using regression coefficients.

Why is lean body mass useful?

LBM is used for medication dosing, estimating metabolic rate, and tracking body composition changes independent of total weight.

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