Beer-Lambert formula
A = ε × l × c, where A is dimensionless absorbance, ε is molar absorptivity, l is path length, and c is concentration. The calculator rearranges this relationship for the selected target.
Unit check
Use ε in L/(mol·cm), path length in cm, and concentration in mol/L. A millimetre path is normalized to centimetres before the multiplication. Keep the wavelength and solvent attached to ε when you reuse the result.
Calibration and limitations
A single-point calculation is not a calibration curve. For quantitative reporting, use standards across the working range, inspect residuals, and document blank correction, wavelength, cuvette, and sample matrix. Use the Molarity Calculator when concentration starts from a measured mass and final volume.
Frequently asked questions
Can absorbance be entered as percent transmittance?
No. Convert and blank-correct transmittance before using this A = εlc model.
Does this fit a calibration curve?
No. It calculates one linear relationship; standards and residual review are separate method work.