Picard

This utility makes it easy to convert between base quality values encoded in ASCII (as recorded in a FASTQ or SAM file) and their integer values representing the Phred-scaled probability that each base call is correct (as explained here).

See the FASTQ format documentation for more details on encoding scales.

Enter the ASCII string or Phred value you want to convert in the box below:
Multiple Phred values can be entered separated by commas.