What happens when you convert CHM to EPUB
- The CHM is unpacked by 7-Zip on our conversion server, and its pages are joined into one document in the order of the help file's own table of contents.
- Scripts, style sheets, frames and embedded objects are removed, so the pages come out in a plain, readable style. Pictures stored inside the CHM are kept; anything it would load from the web is not.
- pandoc, the open-source document converter, writes the result as an EPUB e-book with a table of contents, so a manual can be read on any e-reader.
- This conversion runs on our server: the file is uploaded, converted, and deleted together with the result as soon as the result has been sent back to you. Nothing is kept. Files up to 25 MB are accepted.
How to convert CHM to EPUB online
- Press "Choose CHM files" and select one or more files, or drag them onto the box. Files up to 25 MB each can be converted.
- There are no settings to choose: the converter keeps everything the target format can hold.
- Press "Convert to EPUB". The file is uploaded to our conversion server, converted in a few seconds, and deleted together with the result as soon as the result is sent back.
- Save each EPUB with its download button. Our server has already deleted both your CHM and the EPUB by then.
Why convert CHM to EPUB?
CHM files usually come from Windows help files, software manuals and some older e-books. People convert them to EPUB because EPUB reflows to fit any screen and opens in Apple Books, Google Play Books, Kobo and Send to Kindle.
In short, CHM is good at what it was made for, and EPUB is the more practical choice when the file has to open, upload or print somewhere else. CHM opens with a double-click on Windows; a Mac or Linux PC needs an app such as Calibre or xCHM, while EPUB opens in Apple Books, Google Play Books, Kobo and most e-reader apps; a Kindle needs it sent through Send to Kindle.
How to convert CHM to EPUB on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your CHM files in from File Explorer, and press Convert. Each EPUB is saved to your Downloads folder.
On a Mac
Safari, Chrome and Firefox all work. Drag the CHM files from Finder onto the drop zone and the EPUB files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose CHM files. You can pick from Photos or from the Files app. The converted EPUB appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose CHM files and pick them from Files or your gallery. The EPUB is saved to the Download folder, where any file manager can find it.
Best settings for CHM to EPUB
There are no settings: every topic listed in the table of contents is included, in that order.
Topics that exist in the CHM but are missing from its table of contents may be left out, just as the help viewer never shows them.
CHM vs EPUB: the differences
| CHM | EPUB | |
|---|---|---|
| Full name | Compiled HTML Help | Electronic publication |
| Type | e-book | document |
| Created by | Microsoft | the International Digital Publishing Forum |
| First released | 1997 | 2007 |
| Compression | Lossless | Lossless |
| What it holds | HTML pages, images, a contents tree and a search index in one compressed file | chapters as XHTML pages, with images and a table of contents |
| In a browser | opens with a double-click on Windows; a Mac or Linux PC needs an app such as Calibre or xCHM | opens in Apple Books, Google Play Books, Kobo and most e-reader apps; a Kindle needs it sent through Send to Kindle |
| Common uses | Windows help files, software manuals and some older e-books | e-books from stores other than Amazon and free e-book libraries |
| MIME type | application/vnd.ms-htmlhelp | application/epub+zip |
About CHM and EPUB files
What is a CHM file?
CHM packs a whole website of help pages into one compressed file with a contents tree and search index. Windows still opens it, but blocks CHM files downloaded from the internet until you tick Unblock in their Properties, because they can run scripts.
What is an EPUB file?
An EPUB is a ZIP archive of web pages, one per chapter, plus a file that lists their order. That is why its text can be extracted with ordinary web tools.
CHM to EPUB not working? Common problems
- "Files up to 25 MB can be converted." Server conversions have a size limit. Most of a large book is its pictures; a copy with smaller images will convert.
- The CHM will not open on Windows either. Windows blocks help files downloaded from the internet: right-click it, choose Properties and tick Unblock. That block does not affect converting.
- "This file is not really in CHM format." The converter checks every file before it runs anything, so a file of another format renamed to .chm is refused. Choose the page for its real format.
Convert CHM to EPUB from the command line
7-Zip unpacks a CHM into the web pages inside it, which any browser opens and can print to PDF:
7z x input.chm -ohelpConverting on your own computer keeps the file entirely local, which is worth it for very large or very sensitive documents. For everything else, the converter on this page does it without installing anything.
CHM to EPUB converter FAQ
Will I lose quality converting CHM to EPUB?
The text, headings, lists, tables and pictures of every topic are kept. The help file's own styling and scripts are not.
Why is the EPUB a different size from the CHM?
The CHM is tightly compressed, so the EPUB is usually larger, especially with many pictures.
Are my CHM files uploaded?
Yes, for this conversion. A faithful CHM to EPUB conversion needs 7-Zip and pandoc, two open-source tools, which cannot run in a browser. The file travels over an encrypted connection, is converted in a private temporary folder, and is deleted together with the EPUB as soon as the result has been sent back to you. We do not keep, read or share it.
Can I convert several CHM files to EPUB at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open an EPUB file?
EPUB opens in Apple Books, Google Play Books, Kobo and most e-reader apps; a Kindle needs it sent through Send to Kindle. EPUB is common for e-books from stores other than Amazon and free e-book libraries.
Is this CHM to EPUB converter free?
Yes. There is no sign-up and no watermark. Because this conversion uses our server, there is a fair-use limit of 25 MB per file and a number of files per hour, which stops the service being overloaded.
Can I convert CHM to EPUB on my phone?
Yes. It works in Safari on iPhone and iPad and in Chrome on Android. The conversion happens on our server, so it is as fast on a phone as on a computer; the EPUB is saved to your Downloads folder.