What Is a BSA File?

This article explains what a BSA file is and how to open one on your computer.

What Is a BSA File?

A file with the BSA file extension is a BSARC compressed archive file. The BSA stands for Bethesda Software Archive.

These compressed files are used to hold resource files for Bethesda Softworks computer games, like the sounds, maps, animations, textures, models, etc. An archive makes organizing data much easier than having it exist in dozens or hundreds of separate folders.

BSA files are stored in the \Data\ folder of the game's installation directory.

How to Open a BSA File

The Elder Scrolls and Fallout are two video games that may associate with BSA files, but these applications automatically make use of them when they're in the proper folders—you can't use these programs to open the file manually.

To open one to view its contents, you can use the BSA browser or BSA Commander. All three programs are standalone tools, which means you just need to download them to your computer in order to use them (i.e., installation is unnecessary).

If the file doesn't open in any of the above programs, you may have better luck with Fallout Mod Manager or FO3 Archive. These tools are designed to open BSA files from Fallout, and may even allow you to edit them, providing a clever way to customize gameplay.

How to Convert a BSA File

Converting a BSA file to another archive format (like ZIP, RAR, or 7Z) probably isn't something you want to do. If you did this, the video game that uses the file would no longer recognize the archive, which means the contents of the BSA file (the models, sounds, etc.) wouldn't be usable by the game.

However, if there are files within a BSA file that you want to convert for use outside the video game (e.g., audio files), you can use a file unzip tool to extract/unpack the data, and then use a free file converter to convert the files to other formats.

For example, maybe there's a WAV file inside the archive that you want in the MP3 format. Just extract the WAV file and then use a free audio file converter to complete the conversion.

Still Can't Open It?

If your file still isn't opening even after trying the programs above, re-read the file extension to make sure you aren't confusing it with a file format that shares similar file extension letters.

For example, a BSB file (BioShock saved game) is created by BioShock—you can't open that file with the programs mentioned above even though the file extension is similar to BSA.

BSS is another example. This file extension belongs to the background image format used with the Resident Evil PlayStation game. BSS files can be opened on a computer with Reevengi, not any of the file openers from above.

If the file's suffix isn't ".BSA," research its real file extension to learn which programs can be used to open or convert it. You might even have luck opening the file as a text document with a free text editor.

More on BSA Files

The Elder Scrolls Construction Set Wiki has some useful information on BSA files, including how to create your own.

You can read more about this format at The Garden of Eden Creation Kit (G.E.C.K.) from Bethesda Softworks. Also from G.E.C.K. is a page with information on advanced modding techniques for changing how the game works through altering the BSA files.