Oligo Concentration Calculator

Use an absorption measurement from a spectrophotometer and the extinction coefficient to quickly confirm the concentration of oligos in solution.

Diluted sample OD260 reading

Stock dilution factor (fold dilution)

Oligo extinction coefficient (epsilon)

Example: ε₂₆₀ = 100,000 M^-1 cm^-1

calculate

Concentration of stock:

Important notes

The extinction coefficient at 260 nm is found on Biosearch Technologies’ certificate of analysis for each synthesized oligo. Alternately, it can be obtained using the OligoSpec™ Calculator. It is an estimation based upon composite values for each modification and base. The Extinction Coefficient 260 (ε260) is calculated with the formula, ε260 = [(Sum of ε260 for all bases*) + (ε260 for all modifications*)] x 0.9, to adjust for hyperchromicity. All ε260 values are reported in units of M^-1•cm^-1. ε260 of bases = dA (ε260=15,200), dC(ε260=7,050), dG(ε260=12,010), and T(ε260=8400).

*The extinction coefficient values for all other bases and modifications can be found on BiosearchTech.com under the "Technical Specs" tab available for each oligo modification, or by downloading this PDF.