Performs automated primer design around a specifiied sequence, using default or customised parameters. Square brackets can be placed around the sequence (e.g. exon) to mark it as the target amplified region. The user should indicate to the algorithm the wider region to be flanked by primers by enclosing it within "<" and ">" symbols.

Can be used to obtain primer sequences for multiple exons (in a genomic DNA sequence) at once. It uses the Primer3 program for the design of each primer pair.

Can be used to calculate annealing temperatures of specific oligonucleotide primers such as those designed manually. Note that Primer3Plus provides annealing temperature information within its output data and provides automatic forward and reverse primer pairing based on calculated melting temperatures.

Provided by the National Genetics Reference Laboratory at Manchester, UK. It provides a useful check that the primer sequences chosen do not contain any SNPs that could potentially interfere with primer annealing and thus cause allele drop-out during PCR.

Based at UCSC. It carries out a virtual PCR using the user's chosen primer sequences and shows whether the primers are likely to generate non-specific products.

A page of links to many specialised additional online PCR design tools, provided by a university in Ontario, Canada.