.CHM File Extension

Compiled HTML Help File

Developer Microsoft
3.7  |  93 Votes

What is a CHM file?

A CHM file contains help documentation compiled and saved in a compressed HTML format. It may include text, images, and hyperlinks. CHM files are used by Windows programs as an online help solution. They are compressed using LZX compression.

More Information

Screenshot of a .chm file in Microsoft HTML Help Executable
CHM file open in Microsoft HTML Help Executable

As help documentation has improved and progressed toward website and browser-based formats, the CHM format has largely been retired. Most programs no longer use CHM-based help documentation, and most programs that previously opened CHM files are either unmaintained or no longer open CHM files.

NOTE: While CHM files typically contain help documentation, some contain eBooks.

How to open a CHM file

In Windows, you can open a CHM file by double-clicking it. When you do, the CHM file will appear within Microsoft HTML Help Executable.

If your CHM file contains an eBook, you can open it in Calibre (multiplatform) or another eReader that supports the CHM format.

How to convert a CHM file

You can use G.D.G. Software Chm To Exe (Windows) to extract the .HTM files, images, and other constituent files a CHM file contains. You can also use Chm To Exe to convert a CHM file to the .EXE format. However, to complete the conversion to the EXE format, you must also install G.D.G Software HTML Executable.

Open and view .CHM files with File Viewer Plus.Free Download

Programs that open CHM files

Verified by FileInfo.com

The FileInfo.com team has independently researched the Compiled HTML Help file format and Mac, Windows, and Linux apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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