Sejda PDF

Split by bookmarks

One file per chapter, straight from the table of contents.

Drag & drop your files here

Supported: PDF

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About Split by bookmarks

If the document has bookmarks, they already describe its structure. Choose a bookmark level and every entry at that level becomes a separate, sensibly named document.

  • Filenames taken from bookmark titles
  • Any outline depth
  • Perfect for manuals and reports

How to split by bookmarks

  1. 1

    Upload a bookmarked PDF

    The outline tree is read automatically.

  2. 2

    Pick the level

    Level 1 for chapters, level 2 for sections.

  3. 3

    Split

    Files are named after their bookmark titles.

A practical guide to split by bookmarks

Why bookmarks are the cleanest split key

A long manual, contract or annual report that already carries an outline has told you exactly where its natural seams are. Splitting by those bookmarks means you never count pages or guess where a section ends, and the resulting files inherit meaningful names instead of part-1, part-2. This is ideal for handing a single chapter to a reviewer, posting one policy from a combined handbook, or breaking a merged scan back into the documents it was assembled from, as long as each of those documents starts at its own bookmark.

Picking the right outline level

The level you choose decides how coarse or fine the split is. Level 1 typically maps to chapters or top-level parts and gives you a handful of substantial files; level 2 drops to sections and produces many smaller ones. Preview the chapter list the tool reads back before confirming, because a document with an uneven outline, say some chapters subdivided and others not, can produce lopsided files. If the split looks wrong, the outline itself is usually the cause rather than the tool.

What to do when the outline is missing or messy

If a PDF has no bookmarks, or its outline is decorative rather than structural, splitting by level has nothing reliable to work from. Build a proper outline with the bookmarks tool first, generating entries from the document's headings, then come back and split. When even that is not practical, fall back to splitting by page range or by a repeating text value on each page. Whichever route you take, keep the original combined file, since re-merging split parts and rebuilding an outline by hand is far more work than splitting again.

Frequently asked questions

Two chapters share one page. Where does the split land?
Splits happen at page boundaries, so a bookmark that points partway down a shared page starts its file at the top of that page. The overlapping page ends up in both neighboring files. If clean breaks matter, insert a blank page before each chapter first so no two entries share a sheet.
Some bookmarks point to the same page. Do I get empty files?
Consecutive bookmarks on the same page collapse into one part rather than producing a zero-page file. You will get one document covering that page with the earliest matching title, which keeps the output tidy for densely bookmarked references.
How are duplicate or illegal characters in bookmark titles handled?
Titles become filenames, so characters a file system rejects, such as slashes or colons, are swapped for safe equivalents, and two entries with identical text get a numeric suffix so nothing overwrites. Very long titles are trimmed to a sensible length.
Can I split on level 2 while keeping the level 1 title in the name?
Yes. Choose the depth you want each file to represent, and the parent chapter can be prefixed to the section name so a file reads like Chapter-3_Installation rather than a bare section title floating without context.

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