Oligo Calculator

Enter Oligo Sequence in Box
Length Melting Temperature (Tm) °C
%GC content Molecular Weight: daltons (g/M)
OD of 1 is equal to picoMolar.
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This page was written in Javascript by Eugen Buehler
Research Support Facilities
Deptarptment of Molecular Genetics and Biochemistry
University of Pittsburgh School of Medicine
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A Useful Hint From Bharat Patel's Laboratory

The OligoCalculator calculates Tm based on 0.195M monovalent cation (salt) concentration equal to 1x SSC. For calculating Tm values of oligonucleotides (10 to 50) at different monovalent cation concentrations, the formula given below is used. Using the Oligocalculator and the formula, you can calculate the Tm of your favourite oligonucleotide amplification primers eg in the Promega PCR buffer (which contains 0.05M monovalent cations) or the Tm of your DIG-labelled oligonucleotide probes which are usually used with 0.975M monovalent cations (5x SSC).

Required Tm= Known Tm + 16.6log (required salt concentration / 0.195M), where the Known Tm is calculated from 0.195M using the OligoCalculator.