Split a PDF by bookmarks — at any level, not just the top.
Acrobat's automatic "split by bookmarks" tool only cuts at the top level of the bookmark tree — every nested chapter, sub-section, or appendix underneath gets folded into whichever top-level file it sits under. Long reports and manuals are usually bookmarked several levels deep, so that top-level-only limit leaves most of the real structure unsplit. Here's a way around it, entirely in this browser tab.
No signup. No install. Free for files up to 30 pages.
Neither Acrobat's bookmark split nor this tool reads a nested bookmark tree directly
Acrobat Pro's bookmark-split feature only divides at the top level of the outline — it doesn't walk down into nested chapters or sub-sections. PDF SmartSplit doesn't parse the raw bookmark/outline structure either — reading that data at any depth is on our Pro roadmap, not shipped yet.
The workaround below sidesteps both limits: almost every bookmark, at every level, points to a heading that's also printed as real text on the page — a chapter title, a section number, a sub-heading. Match on that printed text instead of the bookmark structure, and the nesting level stops mattering — a level-3 sub-section heading splits exactly as cleanly as a level-1 chapter.
How to split a PDF by bookmarks at any level today
Three steps, using the heading text a bookmark points to instead of its position in the outline tree.
Pick the nesting level you actually want
Open the bookmarks panel and decide whether you want one file per top-level chapter, or one file per nested sub-section — then note the exact heading text printed at the top of each one you want to split on.
Drop the PDF in below
Switch to "wherever this text appears" mode and paste in that heading text. It loads into your browser's memory only — nothing is uploaded.
Download one zip, one PDF per matched heading
A new file starts every time that heading text shows up on a page — regardless of what level it sits at in the bookmark tree.
pdf.js to read the
text and pdf-lib to
assemble each section's pages into their own file, both running as JavaScript in this page.
Split your bookmarked PDF, any level
Free tier: 1 file at a time, up to 30 pages. Text-layer PDFs only (no scanned/OCR yet).
Drag & drop your bookmarked PDF here, or click to choose
Up to 30 pages · stays on this device
Preview
Split mode
Want us to read your actual bookmark tree — at any depth?
Splitting directly from a PDF's embedded outline — walking every level, without needing matching page text at all — is planned for the Pro roadmap, alongside content-aware renaming, multi-file batch processing, and unlimited pages. Not shipped yet, but it's next.
See Free vs Pro →Your document never leaves your browser
PDF SmartSplit has no upload endpoint, no server that touches your document, and no account to leak. Open your browser's network tab while you split a file — you'll see it stay quiet. Processing uses pdf.js and pdf-lib running as JavaScript in this tab; the zip is built in memory and handed straight to your browser's download dialog.