CHM is Microsoft's compiled help format: HTML topics, images and an index compressed into one legacy-but-everywhere file. Old software manuals, ebooks and documentation still ship as CHM.
Typical use: Extract a CHM to ZIP/HTML to read its topics in a modern browser instead of the deprecated WinHelp viewer.
About the CHM format
CHM (Compiled HTML Help) is Microsoft's format for bundling HTML topics, images and a searchable index into one file. An entire generation of software manuals, programming references and even novels shipped as CHM — and modern Windows no longer renders it comfortably.
Extracting a CHM gives you back the raw HTML topics and images: open them in any browser, convert them onward to PDF or EPUB, or migrate the content into a modern documentation system. The help tree becomes regular files.
Strengths
- ✓ Unlocks decades of locked-in documentation
- ✓ Topics come out as clean, standalone HTML
- ✓ No deprecated viewer required
Limitations
- ✗ Index and search metadata do not convert
- ✗ Topic filenames are often opaque codes
- ✗ Some CHM files use encodings that need care
- Compression
- LZX
- Encryption
- None
- Bundling
- HTML topics + index in one file
- Best for
- Legacy software manuals
Convert CHM to…
12 direct directions, sorted A–Z; 🔥 marks popular targets.
Frequently asked questions
What is a CHM file?
CHM is Microsoft's compiled help format: HTML topics, images and an index compressed into one legacy-but-everywhere file. Old software manuals, ebooks and documentation still ship as CHM.
How do I convert CHM files online?
Pick a target format from the "Convert CHM to…" list below, drop your file and hit convert. Everything runs in your browser — no install, no upload, no watermark, no limits.
Is it safe to convert CHM files here?
Yes. Every conversion is performed by your own device inside the browser — files never leave for a server, and the page keeps working even offline.
Which formats can CHM convert to?
This page lists all 12 directions across documents, images, audio, video, spreadsheets and archives — each one is its own free converter page.