Beer-Lambert Law Calculator
Calculate absorbance, molar attenuation coefficient, concentration, or path length using the Beer-Lambert Law.
Calculation Parameters
Input your parameters below.
Calculated Result
Expert Tip
Make sure all values are in the correct units to ensure mathematically precise chemical results.
How this Calculator Works
This calculator allows you to solve Beer-Lambert Law problems dynamically. Adjust the input parameters using the sliders or selection menu below:
- Molar Absorptivity (ε, L·mol⁻¹·cm⁻¹) (Range: 100 to 50000, Default: 5000)
- Concentration (c, mol/L) (Range: 0.00001 to 0.005, Default: 0.0001)
- Path Length / Cell Width (l, cm) (Range: 0.1 to 10.0, Default: 1.0)
The results are computed instantly and updated in the results panel on the right.
Formula & Methodology
Where:
- Molar Absorptivity: Parameter value.
- Concentration: Parameter value.
- Path Length / Cell Width: Parameter value.
Step-by-Step Calculation Example
To calculate Beer-Lambert Law manually, follow these steps:
- Identify the input parameters. For example:
- Molar Absorptivity (ε, L·mol⁻¹·cm⁻¹) = 5000
- Concentration (c, mol/L) = 0.0001
- Path Length / Cell Width (l, cm) = 1.0
- Apply the formula:
A = ε · c · l
- Verify the calculated value which is updated instantly in the results panel on the right.
Frequently Asked Questions
What is the Beer-Lambert Law equation? ▼
A = ε × c × l, where A is absorbance, ε is molar absorptivity (L/(mol·cm)), c is molarity (mol/L), and l is path length (cm).
What is the relationship between absorbance and percent transmittance (%T)? ▼
A = -log10(%T / 100) = 2 - log10(%T).
When does the Beer-Lambert Law deviate from linearity? ▼
Deviations occur at high analyte concentrations (> 0.01 M), due to stray light, chemical equilibria shifts, or solute interaction.