Select Lab Parameters
Enter your known experimental values into the dark notebook interface. Choose presets for DNA, Protein, or standard cuvettes.
Molar Absorptivity Calculator – Determine Absorption Coefficient
Determine Absorbance, Concentration, Path Length, or Extinction Coefficient using the Beer-Lambert Law (A = ε·l·c).
Experimental Data
A = ε · l · c
Solve for missing variable
DNA (260nm)
BSA Protein
NADH (340nm)
1cm Cuvette
Reset
Conclusion
Result
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Enter 3 values to calculate
Transmittance (%T)
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Linearity Check
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Calibration Curve (A vs c)
| Conc. (M) | Absorbance | %T |
|---|---|---|
| Calculated data will appear here | ||
Common Extinction Coefficients
| Molecule | Wavelength | ε (L·mol⁻¹·cm⁻¹) |
|---|---|---|
| dsDNA (Double Stranded) | 260 nm | ~6,600 (per base) |
| ssDNA (Single Stranded) | 260 nm | ~8,500 (per base) |
| ssRNA | 260 nm | ~7,700 (per base) |
| BSA (Protein) | 280 nm | 43,824 |
| NADH | 340 nm | 6,220 |
| Tryptophan | 280 nm | 5,500 |
How Molar Absorptivity Calculator Works
Instantly compute concentration, absorbance, or path length using the Beer-Lambert Law standard formula.
Solve for Unknowns
Leave one field blank (Absorbance, Concentration, or Epsilon) and the calculator automatically rearranges the formula to solve it.
Unit Conversion
Toggle path lengths between cm, mm, or meters. The tool normalizes inputs to ensure Molar (M) calculations remain accurate.
View Calibration Curve
See your data point plotted on a generated standard curve (Absorbance vs. Concentration) to check for linearity.
Quality Control
Get instant warnings if Absorbance > 2.0 (stray light limit) and view Transmittance (%T) calculations alongside results.
Report & Export
Copy the full calculation summary with algebraic steps to your clipboard or print a compact lab report directly.
Key Benefits of Beer-Lambert Tool
Why researchers, students, and chemists rely on this digital lab notebook for spectroscopic analysis.
Beer's Law Engine
Solves the linear relationship $A = \epsilon l c$ instantly without manual rearrangement errors.
Smart Unit Conversion
Seamlessly handles 1mm micro-cuvettes vs. 1cm standard paths while keeping molarity correct.
Bio-Assay Presets
One-click configuration for DNA purity (260nm), BSA Protein (280nm), and NADH quantification.
Stray Light Warning
Automatic alerts when Absorbance exceeds 2.0, flagging results that drift from the linear range.
Scientific Notation
Toggle scientific display mode for high-precision nanomolar or micromolar concentration work.
Calibration Table
Generates a theoretical standard table of concentrations and %T values based on your Epsilon.
Clipboard Ready
One-click copy function formats result, formula steps, and units for pasting into LIMS or ELNs.
Dark Lab Mode
Low-light notebook interface reduces eye strain during long hours of data analysis in the lab.
Who Should Use This Calculator
Whether you're running spectrophotometry assays or studying analytical chemistry, this tool is built for your bench.
Students
Chemistry Students
Verify homework answers for analytical chemistry problems involving path length and concentration calculations.
Biotech
Lab Technicians
Quickly quantify DNA/RNA yield from NanoDrop readings or calculate protein concentration from assays.
Pharma
Pharmacologists
Determine drug concentrations in solution and validate extinction coefficients for novel compounds.
Academic
Educators
Demonstrate the linear relationship between concentration and absorbance visually in lectures.
Industry
Quality Control
Ensure product consistency by verifying dye or colorant concentrations against standard extinction values.
Research
Biologists
Calculate chlorophyll content or enzymatic activity rates (NADH) using standard absorbance wavelengths.
