Beer-Lambert Absorbance

Calculate absorbance from molar absorptivity, path length and concentration.

How this calculator works

Enter molar absorptivity (l/mol·cm), path length (cm), concentration (mol/l). CalcStack applies the displayed formula and reports each intermediate planning value with the units shown.

Formula / method

A = εlc

Worked example

ε 15,000, 1 cm path length and 20 μM concentration yield absorbance 0.3.

Assumptions and limitations

The sample is homogeneous, monochromatic light is used and Beer-Lambert linearity holds.

Scattering, high concentration, stray light and chemical changes can break linearity.