# What is reading order?

Source: https://epubcc.com/glossary/reading-order/ (updated 2026-11-04)

Reading order is the sequence in which text is meant to be read: column by column, with side notes, captions and footnotes placed where they belong. In an EPUB it is set by the spine and the order of elements in each document.

## Why it matters when you convert a PDF to EPUB

A PDF stores text in drawing order, which can jump between columns, headers and captions. Recovering the reading order is the hardest part of converting multi-column documents: reading straight across two columns mixes two unrelated sentences on every line.

How EpubCC handles it: the engine cuts each page recursively at its widest gaps (an XY-cut), treating a vertical gap as a column break only when each side has at least two lines, and keeps images in the flow as pseudo-words. A paragraph interrupted by a column or page break is joined to the next part when the sentence continues in lowercase.