PAQ is a compression program for the compressed archive files, which usually has the highest data compression rate compared to other formats, at the expense of very long lead times and high memory consumption. PAQ is a command line program, which is open source, but still does not have a GUI. Such is FrontPAQ or eg PeaZip for Windows and Linux.

PAQ was originally developed as PAQAR by Matt Mahoney and has since been improved by different authors.

Properties of the PAQ - Packers

PAQ -8 uses context mixing, in which single- predictions of a number of models, combined with a neural network and arithmetic coding, can be used. Before the data are subjected to a pretreatment text ( text pre-processing ), using seven library files (included ), which can be supplemented by other languages. Noteworthy is the treatment of JPEG files with Huffman coding is replaced by a more powerful compression algorithm, which JPEG files can be weiterverkleinert lossless.


Until PAQ9 many different PAQ versions were developed, which were incompatible with each other. On 12 March 2009 the ZPAQ - Level -1 standard was adopted and published version 1.00. Future versions should be compatible with it.