Note: The nucleic acids (DNA, RNA and oligo) solutions with different concentration has different ability aborbing light. When the light wave is 260 nm, the Absorbance of light and the nucleic acid concentration is calculated as:
   C = A/(e * l)
where:
  C: the concentration of the nucleic acid, in µg/ml, which can be converted to other unit by this tool.
  A: Absorbance (OD₂₆₀).
  l: width of the cuvette which used to hold the solution, in cm, usually is 1cm.
  e: Extinction coefficient of DNA, RNA or oligoes, which is as follows:

•1 OD₂₆₀ Unit = 50ug/ml for double stranded DNA
•1 OD₂₆₀ Unit = 40ug/ml for single stranded RNA
•1 OD₂₆₀ Unit = 33ug/ml for single stranded DNA (ssDNA)
•1 OD₂₆₀ Unit = 20ug/ml for single stranded oligo (ssOligo)

Usually the OD260/OD280 values of nucleotide is in the 1.8 to 2.0 range. If the value is lower, considering contaminations like protein.