File Extension Library

.PAC File Extension

  • Developer by: Netscape
  • Category: Web Files
  • Format: Text

What is an .PAC file?

.PAC file extension is created by Netscape. .PAC has been classified as Web Files. The format of .PAC file is Text.

.PAC is Proxy Auto-Config File

Configuration file used by Web browsers to select an appropriate proxy server; contains a JavaScript function named FindProxyForURL that defines rules for choosing a proxy server based on a given URL; used for controlling and load-balancing Internet traffic, especially in corporate environments.

PAC files are enabled in Web browsers by entering the PAC file URL in the proxy connection settings, or by using the Web Proxy Auto-Discovery (WPAD) protocol. When executed, a PAC file returns a string with one or more proxy server URLs.

PAC files typically are hosted on a Web server and are named proxy.pac.

NOTE: Since PAC files contain JavaScript code, they may be edited with a text editor.

List of all softwares that can open the Proxy Auto-Config File
Microsoft Internet Explorer
Mozilla Firefox
Apple Safari
Mozilla Firefox
Mozilla Firefox
File Type 2:

PAC Subtitles File

Developer by: Screen Subtitling Systems Category: Video Files

Proprietary subtitles format created by Screen Subtitling Systems; used for synchronizing closed captions with a video timeline; can be edited with subtitle editing software such as EZTitles and converted to more standard formats, including .SRT and .SUB.

List of all softwares that can open the PAC Subtitles File
Screen Subtitling Systems Wincaps Q4
Screen Subtitling Systems Poliscript Create
Subtitle Edit
File Type 3:

SBStudio II Song File

Developer by: SonicSpot Category: Audio Files Format: Binary

Song format, called a PAC or package file, used by SBStudio; made up of data blocks that store song information and audio data.

List of all softwares that can open the SBStudio II Song File
FMJ-Software Awave Studio
File Type 4:

STAD Graphic File

Developer by: STAD Category: Raster Image Files Format: Binary

Image format used by the STAD program for Atari ST systems; saved as a black and white image with a resolution of 640x400 pixels; considered a high-resolution graphic for Atari computers.

List of all softwares that can open the STAD Graphic File
Lemkesoft GraphicConverter

How to Open .PAC file on different platforms

Open .PAC File on Windows

  • Right-click a .PAC
  • Left-click "Open With" > "Choose another app"
  • Select the program that opens .PAC file and Select check box "Always use this app to open .PAC files" Press "Ok"

Open .PAC File on Mac

  • Right-click (or Ctrl + Left-click) the .PAC file
  • Click "Open With" > "Other.."
  • Then choose another program from the app list and press "Open"
  • Select check box "Turn on" for "Always open in app"

Open .PAC File on Linux

Right click on the .PAC file, choose "Open with" and select a program from the list above

Open .PAC File on iPhone

Select a file. If you don't see an application to open the .PAC file, tap "Share" and choose the right app.
Method 2
Save the file. Then open the app «Files». Touch and hold the file, then release your finger. You will see a black menu bar. After that tap "Share" and select an application.

Open .PAC File on Android

Tap the Settings icon on an Android smartphone, then select «Applications». Click the Settings icon in the upper right corner of the screen, to change the default apps.
If you want to open, edit, save or even convert .PAC files on Android, then your best bet is to download one of the dedicated apps available on Google Play.

How to fix problems with .PAC files

  1. You need to update the application that you normally use to open .PAC files. Only the latest version of the software supports the current .PAC file format
  2. You need to check the .PAC file for viruses. To do this, you need to scan it with a popular antivirus (Norton, Nod32, Kaspersky, Dr.Web, etc.)