Beer-Lambert Law Calculator
A = εlc, with the linearity limit flagged.
Work out Beer-Lambert Law. A = εlc, with the linearity limit flagged. Names the convention that makes the answer wrong.
Absorbance
1
10.000% transmittance
A = εlc, and A = −log₁₀(T). An absorbance of 1 means 10% of the light gets through; 2 means 1%; 3 means 0.1%. Molar absorptivity is a property of the substance at a specific wavelength, which is why it is an input here rather than a constant.
How the Beer-Lambert Law Calculator works
A = εlc, and A = −log₁₀(T). An absorbance of 1 means 10% of the light gets through; 2 means 1%. Above about A = 1 the relationship stops being reliably linear, and this page says so rather than extrapolating quietly.
Also known as: absorbance calculator · beer's law calculator · molar absorptivity calculator · transmittance to absorbance
Frequently asked questions
What is the Beer-Lambert law?
Absorbance equals molar absorptivity times path length times concentration. It underpins every spectrophotometric assay.
How do I convert absorbance to transmittance?
T = 10^(−A). An absorbance of 1 is 10% transmittance, 2 is 1%, and 3 is 0.1%.
Why should I dilute a sample reading above 1?
Because stray light in the instrument and interactions between solute molecules both bend the line at high absorbance. A reading of 2.5 is unreliable; dilute and re-measure.
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