Beer-Lambert Absorbance

Shine light through a coloured solution in a cuvette and watch the beam dim as absorbance builds with concentration, path length, and wavelength — trace the absorption spectrum and read off the transmittance.

Still frame from the Beer-Lambert Absorbance simulation
Free to run with an account

What you can adjust

Molar absorptivity (peak, epsilon_max)
100 – 8000 L/(mol*cm)

How strongly this solute absorbs light AT ITS OWN PEAK wavelength (520 nm here) — a property of the solute itself. At the default 520 nm wavelength setting, this is exactly the absorptivity used; move the wavelength slider away from 520 nm and less of it is used (see the wavelength slider's own hint).

Concentration
0.0001 – 0.01 mol/L

Solute concentration — absorbance A = epsilon * c * l scales linearly with this, per Beer's Law.

Path length (cuvette)
0.5 – 5 cm

How far the light travels through the solution — a standard cuvette is 1 cm. Absorbance scales linearly with this too.

Wavelength
400 – 700 nm

The light's colour and, because this solute absorbs different wavelengths differently, how much of the molar absorptivity above actually applies — defaults to this solute's own peak absorption wavelength (520 nm).