Reflow a PDF on the device or convert it to EPUB

Last updated 12 October 2026

There are two ways to make a PDF readable on a small screen. You can reflow the PDF for the device, with k2pdfopt on a computer or with KOReader on the e-reader itself. Or you can convert the PDF to an EPUB, which is what Finepress does. Each one suits a different kind of PDF.

Which one should I use?

Reflow on the device keeps the look of the page and reads DjVu files. An EPUB gives you text you can search and mark, in a file that opens in any EPUB reader.

• k2pdfopt fits a PDF with tables, equations or diagrams that must keep their look, a DjVu file, and a reader who wants a PDF made for one screen size.
• KOReader fits a reader who already uses it on an e-reader and wants to keep the PDF as the only copy.
• An EPUB from Finepress fits a PDF that is mostly text, a reader who wants to search and keep marks, and anyone who wants the book in Kobo's reader, on a Boox, or through Amazon's Send to Kindle.

What does k2pdfopt do?

k2pdfopt turns a PDF or DjVu file into a new PDF made for an e-reader or phone screen. You run it on a computer, then copy the new PDF to the device.

• It turns each page into an image, finds the areas that hold content, crops them, and puts them together as smaller pages without the wide margins.
• It can reflow lines of text, also on scans, and it finds two-column regions on its own.
• Its output is a PDF, with the page content as it was or as images, and an optional OCR text layer. It keeps the fonts and graphics of the original pages.
• Its default output is set for e-readers with 6-inch screens. Its examples include settings for a phone.
• There are downloads for Windows, macOS and Linux. The Windows version has a built-in graphical interface.

These details come from the k2pdfopt home page, checked on 12 October 2026. The latest release it lists is version 2.55, from 26 December 2023.

How does KOReader reflow a PDF?

KOReader is a reader app for e-readers, Android and Linux computers. It reflows a scanned PDF or DjVu file on the device, with the same k2pdfopt library built in.

Its project page lists Kindle, Kobo, PocketBook, Cervantes and reMarkable among the devices it runs on, and says scanned PDF and DjVu documents can be reflowed with its built-in K2pdfopt library (checked on 12 October 2026). The reflow happens in KOReader as you read, so you need KOReader on the device.

Can a Boox reflow a PDF?

Yes. Boox's own reader has reflow and a mode for pages set in columns. Read a PDF on a Boox covers it.

What does converting to EPUB give me?

An EPUB holds the book as text, not as pages. Any EPUB reader lays it out for its own screen, and the lines rewrap when you change the type size.

• Search and marks: the text is real text, so you can search it. In Finepress you can keep marks and notes and search them too.
• One file for many readers: the same EPUB opens in Finepress, Kobo's reader, a Boox, Calibre and other EPUB readers, and Send to Kindle takes it.
• Cleaner text: Finepress removes running headers, footers and page numbers, puts columns in reading order, joins words split across lines, and rebuilds chapters, so the contents work.
• No upload: the PDF is converted in your browser. There is nothing to install.

An EPUB has limits too. Finepress flattens tables into text, keeps equations as text rather than mathematics, and can lose the order of a complex layout such as a magazine page. It does not open DjVu files. Formats and limits has the full list.

When is reflow on the device the better choice?

When the page itself matters more than the text, or when the file is one Finepress cannot read.

• The PDF has tables, equations or diagrams that must keep their look. k2pdfopt keeps the rendered fonts and graphics of the page.
• The file is DjVu. k2pdfopt and KOReader read DjVu, and Finepress does not.
• The PDF is a scan in a language other than English or simplified Chinese. Finepress's OCR reads only those two, while k2pdfopt works on the page images.
• You already read in KOReader and want to keep only the PDF on the device.

When is an EPUB the better choice?

When the PDF is mostly text and you want to read it like a book.

• You want to search the text, keep marks and notes, or change the type size freely.
• You want the book in more than one reader app, or on a Kindle through Send to Kindle.
• The PDF has running headers and page numbers that would land in the middle of the text.
• You cannot install software, or you use a phone or tablet. Finepress runs in the browser.

How do they compare?

For reading a PDF on a small screen, these are the differences.

The k2pdfopt and KOReader entries come from the k2pdfopt home page and KOReader's project page, checked on 12 October 2026.