Open/Extract CHM File with Freeware on Windows/Mac/Linux

CHM is an extension for the Compiled HTML file format, most commonly used by Microsoft¡¯s HTML-based help program. It may contain many compressed HTML documents and the images and JavaScript they link to. CHM features include a table of contents, index, and full text searching.

Microsoft Compiled HTML Help is a Microsoft proprietary online help format, consisting of a collection of HTML pages, an index and other navigation tools. The files are compressed and deployed in a binary format with the extension .CHM, for Compiled HTML. The format is often used for software documentation.

It was introduced as the successor to Microsoft WinHelp with the release of Windows 98 and is still supported in Windows 7. Although the format was designed by Microsoft, it has been successfully reverse-engineered and is now supported in many document viewer applications.

Help is delivered as a binary file with the .chm extension. It contains a set of HTML files, a hyperlinked table of contents, and an index file. The file format has been reverse-engineered and documentation of it is freely available.

The file starts with bytes "ITSF" (in ASCII), for "Info-Tech Storage Format".

CHM files support the following features:

  • Data compression (with LZX compression)
  • Built-in search engine
  • Ability to merge multiple .chm help files
  • Extended character support, although it does not fully support Unicode.

Open/Extract CHM File on Windows

Open/View CHM File on Windows:

You can simply double-click on CHM file to view CHM by Windows built-in CHM viewer program. There are also third-part freeware that open CHM file. For example:

  • CHM Viewer
  • Sumatra PDF
  • XCHM
  • FBReader

Extract/Decompile CHM File on Windows:

Easy 7-Zip extracts/decompiles CHM file easily on Windows. The Easy 7-Zip was developed based on 7-Zip. 7-Zip is a famous open source file archiver. The Easy 7-Zip is an easy-to-use version of 7-Zip. The open source freeware keeps all features of 7-Zip and adds a few useful features that makes the software more user-friendly.

Easy 7-Zip works on Windows 10/8.1/8/7/Vista/2008/2003/XP/2000 (both 32-bit and 64-bit compatible).

  1. Free Download Easy 7-Zip
  2. Install Easy 7-Zip by step-by-step instructions
  3. Open CHM file with Easy 7-Zip
    Easy 7-Zip
    You will see files or folders within the CHM file then, click button Extract to extract the CHM file.

  4. Alternatively, Right-click on CHM file on Windows Explorer

  5. And then, choose Extract files..., Extract Here, or Extract to "folder\" to extract the CHM file.

  6. Done

Easy 7-Zip Download Links:

You can try other alternative freeware that extracts/decompiles CHM file on Windows. For example:

  • PeaZip
  • B1 Free Archiver
  • Zipeg
  • Universal Extractor
  • Bitser

Open/Extract CHM File on Mac

Open/View CHM File on Mac:

You need to install CHM viewer software to view CHM on Mac. You can choose one or more the following CHM viewer freeware.

  • Chmox
  • iChm
  • XCHM
  • FBReader
  • Apple Safari
  • Mozilla Firefox

Extract/Decompile CHM File on Mac:

B1 Free Archiver extracts/decompiles CHM file on Mac. B1 Free Archiver is a free software for creating archive folder and extracting archive file. B1 Archiver works on all platforms - Windows, Linux, Mac and Android. The freeware supports most popular formats including CHM.

B1 Free Archiver is compatible with:

  • Mac OS X 10.9 Mavericks
  • Mac OS X 10.8 Mountain Lion
  • Mac OS X 10.7 Lion
  • Mac OS X 10.6 Snow Leopard

Open/Extract CHM File on Linux

Open/View CHM File on Linux:

You need to install CHM viewer software.

Desktop CHM Viewer Software
GNOME gnochm or chmsee
KDE kchmviewer

Another software is xchm.

Convert CHM to PDF on Linux:

You need to install conversion utility chm2pdf.

Install chm2pdf on CentOS and Fedora

# yum install chm2pdf

Install chm2pdf on Debian and Ubuntu

# apt-get install chm2pdf

Convert CHM to PDF on Linux

$ chm2pdf input.chm output.pdf

Extract/Decompile CHM File on Linux:

You need to install libchm-bin.

Install cabextract on Debian and Ubuntu

# apt-get install libchm-bin

Extract/Decompile a CHM file, type:

$ extract_chmLib book.chm output_dir

You can also use p7zip to decompile CHM file, just install p7zip-full, and then use command 7z to extract file from CHM file.

$ 7z x book.chm



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