How to Convert PDF or FB2 to EPUB for an E-Reader

EPUB is the most widely compatible ebook format: it's supported by iPhone, iPad, Android, PocketBook, and most reading apps. If a book came to you as a PDF or FB2 and your reader doesn't understand EPUB, it's worth converting the file.

Converting FB2 to EPUB

FB2 is common mainly in Russian-language libraries, and outside that ecosystem almost nothing reads it — iPhones, iPads, and most Western apps can't open such a file directly. The FB2 to EPUB converter fixes this in seconds: upload the FB2 file, and Calibre on the server assembles an EPUB with the chapter structure, table of contents, and illustrations preserved. The conversion is reliable, since both formats store the book as structured text rather than page images.

Converting PDF to EPUB — with a caveat

Here it's important to understand the difference between two kinds of PDF:

• A PDF with a text layer — a file originally created from text (Word, page layout software, an export from a reading app). It contains real text that can be selected and copied.
• A scanned PDF — a set of photographed or scanned pages packed into a PDF. Visually it looks like text, but it's actually images.

The PDF to EPUB converter handles the first type well: the text is extracted and turned into a "reflowable" EPUB that adapts to the reader's screen. With the second type — scans — the converter can't do anything: there's no actual text in the file to extract, only images, so the result will be unreadable or empty.

Checking which kind of PDF you have is easy: try selecting text in the file with your mouse. If it selects — the conversion will work well. If it doesn't (the whole page gets selected as one block, like an image) — you're looking at a scan, and what you need is text recognition (OCR), not a straight format conversion.

What doesn't carry over perfectly

Even with a text-based PDF, expect small discrepancies: complex tables and multi-column layouts sometimes shift when converting from a fixed page layout into EPUB's reflowable text. For ordinary fiction or business-document text, that's not an issue — the differences mainly show up in technical documents and textbooks with complex formatting.

Bottom line

FB2 to EPUB converts without loss — it's essentially just swapping the container around the same structured text. PDF to EPUB works well for files with a text layer and doesn't work for scans — in that case, only text recognition can help, not a format change.