The melting temperature T_M, characterises the stability of the DNA hybrid formed between an oligonucleotide and its complementary strand.

For your convenience, please use our Oligo Analysis Tool or apply the formula below:

Sequences with 15 or less bases 
T_M [°C] = 2(n_A + n_T) + 4(n_G + n_C)

Sequences with more than 15 bases
T_M [°C] = 69.3 + [41(n_G + n_C) / s - (650 / s)]

n = number of nucleosides of type X 
s = number of all nucleosides per sequence 


Example:
Sequence: GAA ATG AGT GCT CAT CAC TAC TTC CGC (27mer)

nA=7; nC=8; nG=5; nT=7 s= 27

Sequences with 15 or less bases
T_M [°C] = 2(7 + 7) + 4(5 + 8) = 80.0

Sequences with more than 15 bases
T_M [°C] = 69.3 + [41(5 + 8) / 27] - (650 / 27) = 69.3 + 19.7 - 24.0 = 65.0