A while ago, a friend was thinking about buying an ereader for her husband, who reads a lot of PDFs. She thought it would be great for him to be able to read them on an eink device. She asked for advice, and this post is based on what I told her.

Screenshot of a PDF displayed on a Kindle Paperwhite
Reading a PDF on a Kindle Paperwhite. The page size is A4, but the Kindle has a 6″ screen, so the text is very small and difficult to read.

There are many articles online claiming that Kindles and other ereaders support PDF, or how easy it is to convert PDF to your ereader’s preferred format. They’re right, but with some significant caveats. Reading a PDF on an ereader is a far cry from reading an ePub or mobi format ebook on the same device. The PDF won’t resize and reflow to work nicely on the screen. This leads to a lot of zooming and scrolling. I found it such an unpleasant experience that I bought a 10″ tablet to read PDFs on. I still prefer my Kindle and my Kobo for reading ebooks, but won’t use them for PDFs.

Screenshot of a PDF on a Kindle, zoomed in so that the text is large enough to read.
The same PDF on the same Kindle, zoomed in to make the text large enough to read. The user has to scroll horizontally to read each line.

So, why not convert the PDF to ePub or mobi, and read that on the ereader? Converting PDFs is simple enough using Calibre, but the results are very uncertain. The Calibre manual states that “PDF documents are one of the worst formats to convert from.” If it’s a single-column PDF it might work reasonably well. It won’t be as pretty as the original, paragraph breaks might be in odd places, etc. If the PDF has headers and footers, they will be included in the converted file as if they were a standard part of the text, which can be jarring.

Screenshot of a PDF converted to mobi and displayed on a Kindle Paperwhite.
The same PDF converted to a mobi file to read on a Kindle.

Two-column PDFs won’t convert well at all. The converter doesn’t recognise the columns, and so you get the first line of the first column, then the first line of the second column, second line of the first column, second line of the second column, etc. The result is unreadable. Text boxes and the like can also really mess with it.

If you’re going to read a lot of PDFs, I would strongly recommend something with a 10″ or larger screen. 10″ tablets are common and some are reasonably inexpensive, but many people don’t like reading on a back-lit screen, hence the popularity of eink devices for reading ebooks. Kobo recently announced the Kobo Elipsa, which has a 10.3″ eink screen. This should be excellent for reading PDFs and ebooks, but it’s significantly more expensive than either a standard ereader with a 6″ screen or a 10″ tablet.