NEB Tm Calculator

Use this free neb tm calculator to estimate the melting temperature (Tm) of a DNA primer from its sequence.

How the neb tm calculator works

Under 14 bases the Wallace rule is used: Tm = 2(A+T) + 4(G+C). Longer primers use Tm = 64.9 + 41 × (G+C − 16.4) ÷ N.

Frequently asked questions

Is this the same as the NEB Tm tool?

No. This is a quick basic estimate. Nearest-neighbour tools that account for salt and polymerase give different values.

Results are estimates for general information only. They are not a substitute for professional advice where applicable. Found a mistake? Report an error.