Convert the PDF to EPUB and your e-reader can reflow the text — changing size, margins and orientation to fit the screen instead of showing you a shrunken page. You can convert PDF to EPUB in your browser with nothing uploaded. How well it turns out depends almost entirely on what kind of PDF you started with, which is the part most guides skip.
Why a PDF reads badly on an e-reader
A PDF is a fixed-layout format: it describes a page of a specific size with text at specific coordinates. That is exactly what you want for a contract or a form, and exactly what you do not want on a six-inch screen. The reader cannot make the text bigger without making the page bigger, so you end up pinching, panning, and reading a column and a half at a time.
EPUB is the opposite — it stores the text as a flowing document and lets the device decide how to lay it out. Change the font size and the words rewrap. That is the entire reason to convert.
When the conversion works well
Straightforward, text-first PDFs convert cleanly: novels, reports, manuals, articles — anything that is essentially paragraphs running down a single column. The text is already in the file as text, so it comes across as text, and the result reads like a proper ebook.
When it doesn't
- Scanned documents, which contain photographs of words rather than words — there is no text to extract until you run OCR on the scan first
- Two-column academic papers, where the reading order gets interleaved and you end up with alternating half-sentences
- Textbooks and technical manuals, where figures, captions, sidebars and tables carry meaning through their position on the page
- Anything heavily designed — cookbooks, art books, magazines — where the layout is the content
For that last group, honestly, don't convert. A fixed-layout PDF read on a tablet is a better experience than a reflowed EPUB that has lost its structure.
Getting it onto a Kindle or Kobo
Kobo reads EPUB natively — connect it over USB and copy the file across. Kindle takes EPUB too: Amazon's Send to Kindle accepts EPUB directly and converts on their end, and MOBI was retired as a send format, so EPUB is now the right thing to send rather than a workaround.
Worth knowing: if you email a document to Send to Kindle, it passes through Amazon's servers. Converting locally first at least means only the finished ebook makes that trip, not your original document.
Check it before you commit
Open the EPUB and skim a few chapters, particularly around anything that was a table, a figure or a footnote in the original. Conversion problems cluster there rather than in ordinary prose. If the body text flows properly and the headings survived, you have what you came for. If it is a mess, the source PDF was probably one of the hard cases above — and going back to PDF to text and rebuilding is usually less work than fixing it.