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Molar Absorptivity (Extinction Coefficient) from Absorbance Calculator

ε = A / (c · l) — Beer–Lambert molar absorptivity.

Calculates molar absorptivity ε = A/(c·l) and solute concentration c = A/(ε·l) from absorbance A, path length l, and either ε or c.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

mol/L
cm

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

ε = A / (c · l)

In depth

Calculates molar absorptivity ε = A/(c·l) and solute concentration c = A/(ε·l) from absorbance A, path length l, and either ε or c.