Split by Bookmarks: Levels, Filters and Missing Pages
Splitting by bookmark trusts the document's own table of contents. The tool's job is to decide which level of that outline counts as a chapter, and what to do when the outline is incomplete.
Why this comes up
Outlines are built by whoever produced the PDF, often from heading styles in Word or from a publishing tool. They can nest deeper than expected, mix front matter with chapters, or stop before the last section.
Check before you run it
- Open the outline and count its levels. Level 1 might be parts and level 2 the chapters, or the other way round. Choose the level whose entries are the documents you actually want.
- Filter when the outline mixes kinds of heading. The contains-text option limits split points to entries whose titles match, which keeps unlisted sections from starting files of their own.
- Add the extra page when a chapter loses its tail. If the last paragraphs of a chapter sometimes land in the next file, the include-extra-page option adds one page to each part. Check the first split before running the whole book.
When to reach for it
- A manual nests parts, chapters and subsections. Splitting at the chapter level gives usable files without turning every subsection into one.
- A compilation's outline includes covers and indexes. A contains-text filter on the word Chapter creates files only at the real chapter starts.
One question we get
Does it use the PDF's own bookmarks?
Yes — the tool reads the document's outline and splits at the level you choose, so each chapter or section becomes a file without any manual page counting.
Where it fits
The tools people usually open next to Split by bookmarks:
- Merge PDF — Combine multiple PDFs and images into one document.
- Resize — Change PDF page size and add margins/padding.
- Flip — Mirror PDF pages horizontally or vertically.
Every tool works on a copy, so the original file is never touched. Uploads are stored under an unguessable id and deleted automatically two hours after you last open them; nothing is listed, shared or indexed. More on the security page.