What is the Beer-Lambert law?

For assistance calculating concentration use our Beer Lambert Calculator.

The Beer-Lambert law (or Beer's law) demonstrates the linear relationship between absorbance and concentration of an absorbing species. In general, the Beer-Lambert law is expressed as the following formula:

A = εLc

Where:

• A is the amount of light absorbed by the sample for a particular wavelength
• ε is the molar extinction coefficient
• L is the distance that the light travels through the solution
• c is the concentration of the absorbing species per unit volume

Rearrange the Beer-Lambert equation in order to solve for the molar extinction coefficient:

ε = A/Lc

Use our Extinction Coefficient finder to search for the extinction coefficients of other compounds.