How to Use the PCR Annealing Temperature Calculator
Calculate primer melting temperatures and optimal PCR thermocycling conditions:
Enter Sequence
Type forward or reverse oligonucleotide primer sequence (5' to 3').
Calculate GC%
Engine computes guanine-cytosine ratio (target 40-60%).
Calculate Tm
Applies salt-adjusted melting temperature equations.
Set Thermal Cycler
Set annealing stage temperature on PCR thermal cycler.
Key Features & Thermodynamic Principles
Wallace & Salt-Adjusted Algorithms
Switches automatically between Wallace Rule (<14 bp) and salt-corrected formulas.
GC Content Verification
Monitors primer GC percentage to avoid non-specific secondary structures or hairpins.
100% Private Client Compute
Runs in browser memory with zero tracking or server logs.
PCR Thermocycling Guide: Primer Design & Annealing Kinetics
In Polymerase Chain Reaction (PCR), the annealing step allows oligonucleotide primers to hybridize to single-stranded target DNA. If the annealing temperature ($T_a$) is too high, primers fail to bind; if $T_a$ is too low, non-specific binding produces misprimed unwanted amplicons.
Frequently Asked Questions
?Why is Ta usually set 5°C below Tm?
Setting Ta = Tm - 5°C balances high primer binding yield with stringent specificity.