CHM Converter
Convert files to and from CHM online for free. Fast, secure, and high-quality file conversion with no sign-up or software required.
Maximum file size is 1GB
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What is a CHM file?
The CHM (Compiled HTML Help) format is a proprietary binary documentation format developed by Microsoft for software help files. It encapsulates a collection of HTML pages, hyperlinks, and image assets into a single LZX-compressed archive, indexed via a binary table of contents (HHC) and keyword index (HHK). The format relies on the Information Tech Storage (ITS) file system structure, allowing for rapid random access and full-text search capabilities within the Windows Help environment.
How to open a CHM file
Windows operating systems provide native support via the built-in Microsoft HTML Help Executable (hh.exe). On macOS and Linux systems, which lack the proprietary Windows API, third-party viewers are necessary. KchmViewer is a standard solution for Linux/KDE environments, while xCHM provides cross-platform compatibility for macOS and BSD distributions.
CHM Technical Info
- Full Name
- Microsoft Compiled HTML Help
- Developed By
- Microsoft
- Initial Release
- 1997
- MIME Type
- application/vnd.ms-htmlhelp
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