Lab Calculator Suite
Primer Tm Calculator
Most standard PCR buffers have a final monovalent cation concentration of 50 mM. If you are unsure, using the default value of 50 mM is a safe assumption.
mM
Results:
Length
GC Content
Basic Tm (Wallace)
Salt-Adjusted Tm
Note: These are estimates. The Basic Tm is for very short oligos (14-20 bases). The Salt-Adjusted Tm is generally more suitable for PCR primers (~20-35 bases). For critical applications, consider software with nearest-neighbor thermodynamic calculations.