CPX File

What are CPX files and how to open them

Are you having problems opening a CPX 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 CPX files.

What is a CPX file?

CPX files have multiple uses, and Atari Control Panel applet is one of them. Read more about the other uses further down the page.

Atari Control Panel applet

These CPX files contain the control panel applets used by Atari, a home video game console. The control panel has a screen saver, a clock in the corner, and a configurable blitter. In the control panel, you can change system settings.

How to open CPX files

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

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

Last updated: September 18, 2026

All known file formats using extension .CPX

While Atari Control Panel applet is a popular type of CPX-file, we know of 4 different uses of the .CPX file extension. Different software may use files with the same extension for different types of data.

FreeDOS Code Page Information

FreeDOS Code Page Information files store bitmap character sets (codepages) used by the FreeDOS console to display non-English characters. They are created by the CPIDOS project by packaging multiple 8-bit codepages into a single file format designed for use with FreeDOS's MODE and DISPLAY utilities. Each file holds one or more codepages, but it does not include printer fonts.

These files are prepared when the system is set up for a non-default codepage, for example when using MODE CON CODEPAGE PREPARE (...) to load a Latin-2 or Cyrillic character set. After preparing, one uses MODE CON CODEPAGE SELECT= to activate that codepage. The DISPLAY program also refers to these files to determine what glyphs to show on screen, depending on hardware type (EGA, VGA etc.).

CPX files are compressed with UPX, which is why MODE was updated to support the "infamous CPX file format" - a CPI file (which is the older uncompressed format) is packed into UPX and renamed .CPX. The files contain data for screen fonts only, typically character bitmaps for 256 glyphs per font, and support font heights of 8, 14 or 16 pixels, with character widths fixed (usually 8 pixels wide).

In internal structure the file begins with specific signatures and includes identifiers such as "620X" and "FONT". The very beginning includes bytes 0x81FC at offset 0, and 0x7702CD20B9 at offset 4. These help utilities detect CPX format files.

ImgStar Bitmap

We know that one CPX format is ImgStar Bitmap. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Windows Codepage Translator

Windows Codepage Translator files are plain-text tables used by the Microsoft Code Page Translator facility to map characters between different Windows and OEM/DOS code pages. The operating system or custom ANSI/ODBC translator tools can read them to perform character translation when sending or opening data in mismatched code page settings. These files are useful when communicating between systems or applications that use different 8-bit encodings, enabling consistent display or storage of text by defining exactly which character in one code page corresponds to which in another.

Each file is written in the INI-style format, with simple ASCII text, standard CR+LF line endings, and section headers in square brackets. A section header identifies the source and target code page names using a label like [Windows Latin 1 (1252)/850 (Multilingual-Latin 1)] or similar. Below that, mapping lines list pairs of byte values, typically in "byte_in_source:byte_in_target" form, one per line, often separated by a colon. Such translation files are placed in the Windows/System or SysWOW64 directory so that the Microsoft or BASIS ODBC driver translator can load them when the given mapping needs to be applied for data conversion. Custom mapping files must have the file name ending in cpx.

Files created by this translator always begin with the ASCII string "[Windows" at the very start of the file; the twelfth byte specifically is the character "i" (from "Windows Latin …").

Various apps that use files with this extension

These apps are known to open certain types of CPX files. Remember, different programs may use CPX 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 CPX file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.