What Format Are InfoBooks Books In, and Can You Read Them on Any Device?

Updated

InfoBooks distributes its books as PDF files, and the site states that this format "works on all your devices" — download once and read anywhere. In practice, that means you do not need a Kindle, a Kobo, or any dedicated e-reader app: any device with a standard PDF reader can open the files. The one real limitation is that PDF is a fixed-layout format, so on a small phone screen you will be pinching and scrolling rather than reflowing text the way an EPUB would.

The format: PDF only

Every book on InfoBooks is offered as a PDF. The site's own description is consistent on this point:

  • "PDF Format"
  • "Works on all your devices"
  • "Download once, read anywhere"

There is no mention of EPUB, MOBI, AZW3, or other e-reader formats in the site's materials. If your reading workflow depends on a reflowable format — for example, sending books to a Kindle via Send-to-Kindle, which accepts PDF but renders it as a fixed page image — you should expect a different experience than with native Kindle books.

What "any device" actually means

Because PDF is a near-universal format, the practical requirement is just a PDF reader. That is built in or freely available on essentially every platform:

Device How you read it Notes
Windows / macOS / Linux PC Built-in viewers (Edge, Preview, Evince) or any PDF app Best experience for full-page layouts
iPad / Android tablet Built-in Files/Drive viewers or a PDF app Comfortable for most books
iPhone / Android phone Built-in viewer or a PDF app Readable, but expect zooming on dense pages
Kindle / Kobo e-reader PDF support varies by model Fixed layout; small text can be hard to read
No internet Any of the above, after downloading Files are stored locally

The key point is that "any device" refers to the PDF format being universally supported, not to a sync service. InfoBooks does not describe cloud syncing or a reading app of its own — you download the file and it lives on your device.

Reading offline

The site explicitly frames the model as "download once, read anywhere." Once a PDF is saved to your device, no connection is needed to read it. This also means your reading position and highlights are handled by whatever PDF app you use, not by InfoBooks — so if you switch devices, you will need to move the file yourself or start over.

What to check before you commit

  • Screen size vs. book length. A 300-page classic on a phone is workable but not pleasant. A tablet or computer is the better match for the longer titles in the catalog.
  • Your PDF app's features. Search, bookmarks, night mode, and text-to-speech all come from the reader, not the file. Pick one you like before downloading a stack of books.
  • E-ink devices. If you read mainly on a Kindle or Kobo, test one file first. Fixed-layout PDFs often render with tiny text on 6-inch screens.
  • No special reader required. There is nothing proprietary to install, and the site describes the books as free with no registration — so the only setup cost is choosing a PDF app.

Bottom line

InfoBooks books are PDFs, and PDFs open on virtually any computer, tablet, or phone with a standard reader — no special software, no account, and no connection needed after download. Choose a device with a screen large enough for the page size, and pick a PDF app whose search and bookmark tools you actually like, since those features come from the app rather than from InfoBooks.