CPA File

What are CPA files and how to open them

Are you having problems opening a CPA 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 CPA files.

What is a CPA file?

A .CPA file is a CADSTAR PCB Archive file.

CADSTAR PCB Archive files store a full printed circuit board design in a plain-text archive form used by CADSTAR (now by Zuken). They contain all layout data needed to build or modify a board: design rules, layer stack-up (copper, mechanical layers, etc.), component-footprint definitions, layout of parts with nets/tracks/vias, board outline, copper pour areas, dimensions, and templates.

The archive format is generated when exporting a binary PCB design or PCB library from CADSTAR to its ASCII "archive" style rather than using proprietary binary files. It is often used for design portability, archival, migration, or importing designs into other tools. CADSTAR software writes these files, and other EDA applications (such as KiCad) can read or import them when they have support for the CADSTAR archive format.

Inside each archive the top-level is a parenthesized, S-expression-like structure encoded in Windows-1252 text. The root node is labeled CADSTARPCB (indicating a PCB Archive). Early bytes of the file start with a header containing the signature "CADSTARPCB" (along with HEADER, FORMATLAYOUT, JOBFILE etc.). Also present near offset 43 is the "JOBFILE" field, part of the HEADER section.

How to open CPA files

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

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

Last updated: September 2, 2026

Various apps that use files with this extension

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

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