CHM File

What are CHM files and how to open them

Are you having problems opening a CHM 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 CHM files.

What is a CHM file?

CHM files have multiple uses, and Windows Compressed HTML Help is one of them. Read more about the other uses further down the page.

Windows Compressed HTML Help File

Files with the .chm extension are most commonly associated with Microsoft help documentation files.

The CHM files are compressed to reduce the size and may consist of HTML pages and images. Often you will find an associated CHM file with software you install.

How to open CHM files

We have identified two CHM openers that are compatible with this specific type of CHM file.

Programs that open Windows Compressed HTML Help files

Last updated: December 28, 2023

All known file formats using extension .CHM

While Windows Compressed HTML Help File is a popular type of CHM-file, we know of 2 different uses of the .CHM file extension. Different software may use files with the same extension for different types of data.

Chemdraw Chemical Structure

These files contain data describing a chemical structure. ChemDraw versions earlier than 4.0 used files with extension CHM as the default ChemDraw format. However, Microsoft started to use the same extension for compiled help files, and this caused problems as ChemDraw version 3 and earlier assigned itself as the default opener of CHM files.

CHM opener for Windows

We have identified one CHM opener that is compatible with this specific type of CHM file.

Various apps that use files with this extension

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