Beer-Lambert Law Calculator

Calculate Absorbance & Transmittance

Molar Absorptivity ε (L/(mol·cm))

Path Length l (cm)

Concentration c (mol/L)

Find Concentration from Absorbance

Measured Absorbance (A)

Molar Absorptivity ε (L/(mol·cm))

Path Length l (cm)

Formula

A = ε × l × c. Also A = -log₁₀(T). Where ε is molar absorptivity (L/(mol·cm)), l is path length (cm), c is concentration (mol/L), T is transmittance.

Frequently Asked Questions

What is the Beer-Lambert Law?

The Beer-Lambert Law relates absorbance to the concentration of an absorbing species: A = ε × l × c, where ε is molar absorptivity, l is path length, and c is concentration.

How are absorbance and transmittance related?

Absorbance A = -log₁₀(T), where T is transmittance (fraction of light passing through). A = 0 means 100% transmittance; A = 1 means 10% transmittance.

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