Determine the molar extinction coefficient from absorbance and known concentration.
The extinction coefficient is intrinsic to a compound at a given wavelength and path length. Its magnitude sets the usable concentration range: a large ε gives sensitive detection but saturates at low concentration. Absorbance of 1.0 means only 10 per cent of light passes, which is why the linear range ends not far above it.
Molar Extinction Coefficient
ε = A ÷ (c l); transmittance = 10^(−A)
ε = A ÷ (c l); transmittance = 10^(−A) The extinction coefficient is intrinsic to a compound at a given wavelength and path length. Its magnitude sets the usable concentration range: a large ε gives sensitive detection but saturates at low concentration.
Absorbance of 1.0 means only 10 per cent of light passes, which is why the linear range ends not far above it.
This calculator takes 3 inputs: Measured absorbance, Known concentration, Path length. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.