OD260 Concentration Calculator

Beer-Lambert Law

A = ε × l × c

A = Absorbance (OD260) ε = Extinction coefficient l = Path length (1 cm) c = Concentration

Nucleic Acid Type

OD260 Value (Absorbance)

OD280 Value (optional — for purity)

Dilution Factor (if sample was diluted)

Extinction Coefficients

ssDNA: 33 µg/mL per OD260 unit
dsDNA: 50 µg/mL per OD260 unit
ssRNA: 40 µg/mL per OD260 unit

A 260/280 ratio of ~1.8 indicates pure DNA. ~2.0 indicates pure RNA. Lower ratios suggest protein contamination.

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Results

Extinction Coefficients