CHM File

What are CHM files and how to open them

Are you having problems opening a CHM file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your 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 one CHM opener that is compatible with this specific type of CHM file.

Programs that open Windows Compressed HTML Help files

Last updated: February 24, 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.

HTML HelpHTML HelpUser submitted
Microsoft SQL ServerMicrosoft SQL ServerUser submitted
TouchEn webTouchEn webUser submitted
E-book viewerE-book viewerUser submitted
CalibreCalibreUser submitted
Adobe AcrobatAdobe AcrobatUser submitted
Launch ManagerLaunch ManagerUser submitted
IBM Standard Software InstallerIBM Standard Software InstallerUser submitted
ThinkPad Presentation DirectorThinkPad Presentation DirectorUser submitted
Adobe PhotoshopAdobe PhotoshopUser submitted

Help us help others 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 to discuss further.