Commonly used for everything from program help to e-books, Microsoft’s Compiled HTML Help (CHM) format works very well on the PC. CHM files aren’t always as easy to browse on other platforms, though, so if you need to access their content elsewhere then you might be interested in CHM to PDF.

This free program is extremely easy to use. Just choose your source CHM file, click Convert, and a PDF of the same name (but with a PDF extension) will be produced in the same folder.

There are one or two options. If the PDF files should be as small as possible, then checking “Greyscale” or “Low quality” should help. The documents won’t look as impressive, but if you only want to read the text then there should be no problems.

Choose the source file, click “Convert” – that’s it.

Does it work? We pointed the program at a few very simple CHM files – no navigation tree, just essentially one long, single page – and text, images and formatting were all accurately reproduced.

We tried some more complex files, including the latest VirtualBox help file, almost 5MB of detailed documentation. The resulting PDF had no navigation tree, of course, but otherwise it looked great, with no issues that we could find.

But, there were also problems. The formatting and presentation of a CHM file varies according to how it’s coded, but CHM to PDF doesn’t understand that coding: it just converts all the content in the file, whether you’d normally see it or not, and that can lead to some spectacular failures (multiple blank pages with the occasional line or two of text, for instance).

If you really need to save your files as PDF, then give CHM to PDF a try; it’s free, and worked most of the time for us. But if you need more flexibility, check out CHM Decoder. It converts your files to HTML so they’re still easy to view, but you also get to keep the navigation tree, and of course there’s the option to edit the file if you need to customise it later.