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Beer-Lambert Law Calculator

Absorbance from molar absorptivity, path length, and concentration.

Compute the absorbance of a solution at a single wavelength from the molar absorptivity ε, the path length ℓ, and the concentration c, using the Beer-Lambert law A = ε · ℓ · c.

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

Inputs

M⁻¹·cm⁻¹
cm
M

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

A = ε · ℓ · c; transmittance T = 10⁻ᴬ.

In depth

Compute the absorbance of a solution at a single wavelength from the molar absorptivity ε, the path length ℓ, and the concentration c, using the Beer-Lambert law A = ε · ℓ · c.