What is Parchive?

Parchive is redundant file format. If you lose part of your file in transmission or in storage, you can use a Parchive file to repair it. It's like RAID for files instead of a whole file system.

Parchive's latest version is version 2.0 and its files have the extension ".par2". If you have a ".par2" file (or older ".par" file) and want to repair the original file(s), you can install and run a client program.

Has been around for 20 years and there have been millions of "par2" clients downloaded. "par2" is the de facto standard for safely sending large files on Usenet (a.k.a., "network news") and is built into many newsreaders. It is also used for backups, where people fear a CD/DVD/tape will get damaged or, when using multiple media, a few will fail entirely.

Install and run a Parchive client

Parchive is a file format. It can be read and written by many different programs. (We call these programs "clients".) Below is a list of some of them.

Windows clients

OSX clients

Linux clients

Help with Parchive

Bugs and questions for graphical client should be directed to that client's author. The Parchive developers are only responsible for the file format and the par2cmdline client.

Documentation for the par2cmdline client can be gotten by running "par2 --help" or "man par2" (or "par2cmdline --help" and "man par2cmdline").

Bugs in par2cmdline can be tracked on the Github project's issues page.

Some help is available on the old website on Sourceforge


Specification for Parchive files, version 3 --- ALPHA DRAFT. Currently waiting on a reference implementation before finalizing the specification.

Specification for Parchive files, version 2.

Specification for Parchive files, version 1

Documentation for the par2cmdline client can be gotten by running "par2 --help" or "man par2" (or "par2cmdline --help" and "man par2cmdline").

The old website on Sourceforge has some more information.


Development of par2cmdline program and Parchive file specification are done at the Github project page.

Special thanks to the people who worked on Parchive: Par1 Specification Authors Stefan Wehlus, Tobias Reiper, Kilroy Balore, Willem Monsuwe, Karl Vogel, Ryan Gallagher, Par2 Specification Authors Michael Nahas, Peter Clements, Paul Nettle, Ryan Gallagher, Admins Ike Devolder, Ryan Gallagher, Roger Harrison, Jussi Kansanen, Client Authors Peter Clements, Howard Fukuda, Loek Jehee, Kerry Keal. You all rock.