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Lean Body Mass Calculator — 3 Formulas — Free Online Calculator

Calculate your lean body mass using Boer, James, and Hume formulas simultaneously. Get estimated fat mass and lean mass percentage without body fat.

✓ Formula verified: January 2026For informational purposes only
Goal

LBM Calculator

Results below

Enter Values

ft
in
cm
Average Lean Body Mass (3 formulas)
129.7 lbs

Boer Formula (1984)

131.5 lbs

James Formula (1976)

133.9 lbs

Hume Formula (1966)

123.7 lbs

Total Body Weight

170.0 lbs

Estimated Fat Mass (using average LBM)

40.3 lbs (23.7%)

Lean Mass Percentage

▲ 76.3%

What if your weight changes? 153 → 122.7 lbs · 170 → 129.7 lbs · 187 → 136.4 lbs

Scenario Comparison

Conservative (5%)
$16,470.09
$6,470.09 interest
Your scenario (7%)
$20,096.61
$10,096.61 interest
Aggressive (10%)
$27,070.41
$17,070.41 interest
High-risk (14%)
$40,224.71
$30,224.71 interest
Best return
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BMI CalculatorBody Fat CalculatorIdeal Weight CalculatorHealthy Weight
Body Composition
Lean 76%
Fat 24%

Lean Mass

129.7 lbs

76.3% of body weight

Fat Mass

40.3 lbs (23.7%)

23.7% body fat

Boer

131.5 lbs

James

133.9 lbs

Hume

123.7 lbs

Average LBM across 3 formulas. Boer (1984) is generally considered most accurate. For clinical precision, DEXA or hydrostatic weighing is superior.

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