Primer Melting Temperature
PCR primer melting temperature (Tm), length.
Example
You enter
- Primer sequence (5' -> 3') GCGGATCCATG
- Method auto
You get
- Tm 36
- Length nt 11
Checked against published worked examples from: Wallace 1979 / Marmur & Doty 1962 (primer Tm).
Details, formula, and sources
ScopePCR primer melting temperature (Tm), length, and GC content by the Wallace short-oligo rule (<=14 nt) or the basic GC% formula.
Formula or tableWallace (<=14 nt): Tm = 2(A+T) + 4(G+C). Basic GC% (>14 nt): Tm = 64.9 + 41*(G+C-16.4)/length.
Source and editionPer Wallace R.B. et al., Nucleic Acids Research 6 (1979), for the short-oligo rule and Marmur & Doty, J Mol Biol 5 (1962) / standard references for the GC% formula, by name.
Free accessFree abstracts at pubmed.ncbi.nlm.nih.gov; complements the pcr-master-mix tile.
What governsEstimate. AHJ and licensed professional govern.
API field namessequence, method, tm_c, length_nt
- Method gate Wallace for <=14 nt, GC% formula above; non-ACGT characters droppedWallace 1979 / Marmur-Doty 1962