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)

To calculate absorbance from the Beer-Lambert Law, multiply the molar absorption coefficient by the concentration, then multiply by the path length.

## Beer-Lambert Law Definition

The Beer-Lambert Law, also known as the Beer-Lambert-Bouguer Law or simply Beer’s Law, is a fundamental principle in spectroscopy that relates the concentration of a solute in a solution to the absorption of light by that solution.

It is named after the scientists August Beer and Johann Lambert, who independently formulated the law in the mid-19th century.

The law states that the absorbance (A) of light passing through a sample is directly proportional to the concentration (c) of the absorbing species and the path length (l) that the light travels through the sample. Mathematically, this relationship is represented as A = εcl, where ε is the molar absorptivity or molar absorption coefficient, a constant unique to each absorbing species and wavelength of light.

The Beer-Lambert Law is crucial in various scientific disciplines, particularly chemistry, biochemistry, and environmental science. It provides a quantitative method to determine the concentration of a solute in a solution by measuring the absorbance of light at a specific wavelength.

This enables scientists to analyze the composition and concentration of substances, such as pollutants in water, reactants in chemical reactions, or biomolecules in biological samples.

## Beer-Lambert Law Example

How to calculate absorption from the Beer-Lambert law?

**First, determine the coefficient.**Calculate the molar absorption coefficient of the substance.

**Next, determine the concentration.**Calculate the concentration of the substance.

**Next, determine the path length.**Calculate the length of the path in which the substance can be absorbed.

**Finally, calculate the absorption.**Calculate the absorption using the formula above.

## FAQ

**What is the Beer Lambert Law?**

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