What's so special about B1 Free Archiver and B1 Format

B1 Free Archiver

Simple & fast

B1 Free Archiver is extremely simple to use. Its clear interface and polished look will turn even a trivial file management task into delight. Just install it and enjoy.


B1 Archiver works on most popular platforms - Windows, Linux, Mac, Android and as a web application. It looks and works the same across all devices.


B1 Free Archiver supports almost 40 formats: b1, zip, rar, rar5, 7z, jar, xpi, arj, bz2, bzip2, tbz2, tbz, txz, cab, chm, chi, chq, chw, hxs, hxi, hxr, hxq, hxw, lit, cpio, deb, gz, gzip, tgz, tpz, hfs, iso, lzh, lha, lzma, rpm, tar, xar, z, taz, xz, dmg, cb7, cbr, cbt, cbz.

Version for Android

B1 Archiver for Android works both as a file manager and as an archiver. B1 File Manager presents excellent navigation features and copes with all types of file compression and unpacking.


B1 Archiver is 100% free for both personal and commercial use. No registration, no payment, nothing. Feel free to share B1 Free Archiver with your friends and co-workers.

Safe and secure

B1 Free Archiver is absolutely free from any malware or adware. We apply the highest safety standards and care about your privacy. B1 Archiver never gathers any kind of personal information and does not install any malicious software.

B1 archive format

Innovative technology

B1 archive is an open archive format which combines best proven solutions and our new original ideas. It’s free and available for both personal and commercial use.

Open source

We're happy to share b1 with everyone, all code is open. You can download sources of all b1 tools and libraries here. Feel free to use them in any of your products or services.

Best speed to compression ratio

Though classic LZMA compression has been improving for over a decade, there are still some options to explore. For b1 we designed an improved compression algorithm with much better speed to compression ratio.

Encryption with password

B1 format supports data protection with 256 bit AES encryption algorithm. No one will be able to read or extract original files without a password.

Integrity check

B1 checks every archive’s integrity with the Adler-32 algorithm right before unpacking it.

Developers community

We developed tools and libraries to work with b1 archives. Please refer to project documentation and discussion group. Feel free to ask for support should you have any questions.