pdfcosmos

Split PDF by Bookmark

Turn a bookmarked PDF into one file per chapter, all in your browser.

Free, fast, and privacy-first.

Split your PDF by bookmark

or drag & drop files here

PDF files onlyone file at a timeup to 100 MB each

Split a PDF by bookmark — one file per chapter, outline, or section

Split PDF by Bookmark reads your document's navigation tree — officially the “outline”, shown as “Bookmarks” in Acrobat and Chrome, and usually your chapters — and cuts the file at those boundaries, so each bookmark becomes its own PDF. It's the fast way to break a long, bookmarked report, book, or statement into one file per section without hunting for page numbers. Split by bookmark, by outline, and by chapter all mean the same thing here.

If your PDF has nested bookmarks (chapters with sections inside), a level selector lets you split only at the top level or go deeper for more, smaller files. Each output is named after the bookmark that starts it, with a number prefix so they stay in order (for example 01-Introduction.pdf), and any pages before the first bookmark are kept in the first file so nothing is dropped. Reading and splitting both happen in your browser with qpdf (WebAssembly), so nothing is uploaded. A PDF with no outline is left untouched and the tool tells you so; to split by page numbers instead, use Split PDF.

  • One file per bookmark

    Cut a document at its outline boundaries — chapters or sections become separate PDFs.

  • Split at any depth

    Top-level only, or go deeper into nested bookmarks for more, smaller files.

  • Named and in order

    Each file is named after its bookmark with a number prefix, like 01-Introduction.pdf.

  • Runs on your device

    qpdf reads and splits in your browser via WebAssembly. Nothing is uploaded.

How to split a PDF by bookmark

  1. Add your PDF

    Click “Add PDF”, or drag a single bookmarked file into the upload area.

  2. Choose the level

    The tool reads the PDF's bookmarks (outline). Split at the top level, or go deeper if the PDF has nested bookmarks.

  3. Download

    Click Split. Each bookmark becomes its own PDF, named after it, bundled as a ZIP.

Frequently asked questions

Are my PDF files uploaded to a server?
No. Reading the bookmarks and splitting both happen entirely in your browser using WebAssembly. Your file never leaves your device. You can confirm it in your browser's Network tab.
What is “split by bookmark”? Is it the same as by outline or by chapter?
Yes. They're the same thing. A PDF's navigation tree is officially the “outline”. Viewers such as Acrobat and Chrome show it as “Bookmarks”, and the top-level entries are usually chapters. This tool splits the file at those bookmark boundaries, so one bookmark becomes one PDF.
What does the level (depth) setting do?
Bookmarks can be nested: chapters with sections inside them. “Top level” splits only at the outermost bookmarks (e.g. one file per chapter). Choosing a deeper level also splits at the nested bookmarks, giving you more, smaller files. The selector only appears when the PDF actually has nested bookmarks.
My PDF has no bookmarks. What happens?
Nothing is uploaded or guessed. If the PDF has no outline, the tool tells you so and does nothing. There are no bookmarks to split at. To split by page numbers instead, use the Split PDF tool.
How are the output files named?
Each output PDF is named after the bookmark that starts it (for example “01-Introduction.pdf”), with a number prefix so the files stay in order. Any pages before the first bookmark are kept in the first file, so nothing is dropped.
Why did I get a ZIP file?
A by-bookmark split usually produces several PDFs, so they're bundled into a single ZIP for one convenient download.
Is the quality or content changed?
No. Splitting only copies the existing pages into new PDFs. The page content is untouched, so there's no loss of quality.
Is it free?
Yes, it's completely free to use.