Beer Lambert Law Calculator
Beer-Lambert law calculator
Solve concentration from absorbance, epsilon, and path length.
InputsChemistry3 fieldsLive
Result
0.005 mol/L
Uses c = A/(epsilon × l).
Live update
Chem signal
Advanced options
Formula
A = epsilon x l x c so c = A/(epsilon x l) Symbol legend
| Symbol | Meaning | Unit | Copy |
|---|---|---|---|
A | Measured absorbance | - | |
\varepsilon | Molar absorptivity | L/(mol.cm) | |
l | Optical path length | cm | |
c | Concentration | mol/L |
- Enter absorbance reading A.
- Enter molar absorptivity epsilon and path length l.
- Solve c by dividing A by epsilon times l.
Example
Worked example: A=0.50, epsilon=100, l=1.0 cm
- 1 A = epsilon x l x c
- 2 c = A/(epsilon x l) = 0.50/(100 x 1.0)
- 3 c = 0.005 mol/L
Estimated concentration is 0.005 mol/L.
How
- Enter absorbance value.
- Enter molar absorptivity and cuvette path length.
- Read concentration output in mol/L.
Avoid
- Using path length in mm without converting to cm.
- Ignoring baseline correction and instrument limitations.
- Applying linear relation outside Beer law linear range.
Ref only. Verify values. Follow lab safety.
FAQ
Does absorbance need units?
Absorbance is unitless.
Can epsilon vary with wavelength?
Yes, molar absorptivity depends on wavelength and analyte.
Is this valid for very high absorbance values?
High absorbance can leave linear range; use calibration checks.
Switch
Switch12
No match.