Calculate nucleic-acid concentration from an A260 spectrophotometer or NanoDrop reading using the Beer–Lambert factors for dsDNA, ssDNA, or RNA.
| Concentration (ng/µL) | – |
Use this calculator after you have blanked the instrument and read absorbance at 260 nm. Path length is assumed to be 1 cm, which matches a standard cuvette and most NanoDrop-style pedestals.
Concentration in ng/µL (the same as µg/mL) is A260 × the nucleic-acid factor × the dilution fold used before the reading. The factors are 50 for double-stranded DNA, 33 for single-stranded DNA, and 40 for RNA. Enter 1 if you measured the sample undiluted.
This is a conversion of A260, not a purity check. A260/A280 and A260/A230 still need to be inspected separately. Contaminants that absorb at 260 nm will inflate the result.
A260: The unitless absorbance at 260 nm reported by the instrument.
Dilution factor: How many times you diluted the sample before reading. 1 means neat; 10 means one part sample in ten parts total.
Type: dsDNA for double-stranded DNA, ssDNA for oligos or single-stranded DNA, RNA for RNA.
Concentration (ng/µL): Estimated nucleic-acid concentration, also equal to µg/mL.
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