BAC File

What are BAC files and how to open them

Are you having problems opening a BAC file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BAC files.

What is a BAC file?

BAC files have multiple uses, and Ami-Back Backup is one of them. Read more about the other uses further down the page.

Ami-Back Backup

These BAC files contain the backups of files created with Ami-Back, a backup software used on the Amiga computer, a home computer popular that was popular in the 1980s/1990s.

How to open BAC files

Important: Different programs may use files with the BAC file extension for different purposes, so unless you are sure which format your BAC file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested five different BAC openers which you will find listed below.

Last updated: August 23, 2026

All known file formats using extension .BAC

While Ami-Back Backup is a popular type of BAC-file, we know of 2 different uses of the .BAC file extension. Different software may use files with the same extension for different types of data.

Luxor ABC80 Tokenized BASIC Source

Luxor ABC80 Tokenized BASIC Source files hold ABC80 BASIC programs in a binary form that is partly compiled ('tokenized') so that keywords and syntax are converted into internal codes rather than plain text. These files are created by the ABC80's BASIC interpreter when saving with the SAVE command using the semicompiled format, which allows programs to load and run faster than the plain text version stored via LIST. The tokenized form occupies more space than ASCII-encoded text but is more efficient for execution. Programs in tokenized form are not compatible across machine types if their tokenization differs.

The tokenized source is produced by the ABC80 machine itself or its BASIC interpreter, which semi-compiles input - either typed in or loaded - and when SAVE is used, writes out this internal representation. When such a file is loaded back by the ABC80 (or a compatible emulator set in its mode), the interpreter reads the tokens directly, restoring program structure more quickly than parsing ASCII text. For compatibility or editing, the same program can instead be saved via LIST which outputs plain ASCII text with the extension typically used for text format.

Files in this format begin with specific byte patterns identifying them as tokenized ABC80 BASIC. The first byte is 0x82 at offset 0, and there is a 0x00 at offset 3. These signatures help differentiate this format from other similarly named or extended formats.

Various apps that use files with this extension

These apps are known to open certain types of BAC files. Remember, different programs may use BAC files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about BAC file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.