Enter the molar absorption coefficient, concentration, and path length into the calculator to determine the total absorbance.

Beer-Lambert Law Formula

The following equation is used to calculate the absorbance of a substance.

A = ma * c * l

  • Where A is the absorbance
  • ma is the molar absorption coefficient (m*2/mol)
  • c is the concentration (mol/L)
  • l is the path length (m)

Beer-Lambert Law Definition

The Beer-Lambert law defines the phenomena that the absorbance of a substance is proportional to the product of the concentration and length.

Beer-Lambert Law Example

How to calculate absorption from the Beer-Lambert law?

  1. First, determine the coefficient.

    Calculate the molar absorption coefficient of the substance.

  2. Next, determine the concentration.

    Calculate the concentration of the substance.

  3. Next, determine the path length.

    Calculate the length of the path in which the substance can be absorbed.

  4. Finally, calculate the absorption.

    Calculate the absorption using the formula above.


What is the Beer Lambert Law?

This law states that the absorbance is proportional to the length and the concentration of a material.