How is this different from other online PDF tools?

Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.

Are my PDF files uploaded?

No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.

Can I verify that files are not uploaded?

Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.

Does this tool work offline?

Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.

What happens when I refresh the page?

Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.

Does this tool store my files?

No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.

Can this tool unlock password-protected PDFs?

No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.

What technologies does this tool use?

This tool uses pdf.js to read the bookmark outline and client-side JavaScript with pdf-lib to copy each section into its own PDF — your files never leave your browser.

Does this tool use WebAssembly?

No. pdf.js and pdf-lib are plain JavaScript libraries — no WebAssembly is involved. Everything runs in client-side JavaScript within your browser.

How do I split a PDF by its bookmarks?

Choose a PDF that has a bookmark outline using the file picker, then press the split button. The tool reads the top-level bookmarks in your browser, turns each into a page range, and gives you one named download per section.

Why are my chapter sub-sections not split into separate files?

The tool divides the document at its top-level bookmarks, so any nested sub-bookmarks stay inside their parent section's file. Each top-level bookmark runs until the next one begins, which keeps whole chapters intact rather than fragmenting them.

Why did I get an extra file called "Front matter"?

If the document has pages before the very first bookmark, such as a cover or table of contents, those pages are placed in a separate "Front matter" file so no pages are lost. Output files are numbered and named after each bookmark, like "01-Introduction.pdf".

Does Split PDF by Bookmarks cost anything to use?

Split PDF by Bookmarks is completely free — no account, no sign-up, and no cap on how many PDFs you split or how many bookmark chapters each one contains. The tool reads your PDF's outline, divides it into one file per top-level bookmark, and saves every chapter straight to your device, all inside your browser tab; your document is never sent to a server or any external service, and the tool is free and always will be.

Split a PDF by Its Bookmarks Privately — In Your Browser

Select a PDF with bookmarks; its top-level bookmarks become page ranges and each range is saved as its own named PDF, all locally in your browser.

Quick answer

What it does: Select a PDF with bookmarks; its top-level bookmarks become page ranges and each range is saved as its own named PDF, all locally in your browser.
Free?: Yes — 100% free, no account or sign-up.
Files uploaded?: No — everything is processed in your browser.
Works offline?: Yes — once the page has loaded.
Best for: An editor splits a 200-page annual report into per-chapter PDFs named after each bookmark, ready to send to individual departments.
Good to know: Only top-level bookmarks are used; nested sub-bookmarks stay inside their parent's file.

How it works

Select a PDF file from your device using the file picker.
The file is read into browser memory — no data leaves your browser.
pdf.js reads the bookmark outline and resolves each top-level bookmark to its starting page.
The document is divided into ranges: each bookmark runs until the next one begins.
pdf-lib copies each range into its own PDF, named after the bookmark, and all files are offered as downloads.

When to use this tool

An editor splits a 200-page annual report into per-chapter PDFs named after each bookmark, ready to send to individual departments.
A student splits a combined textbook PDF by its chapter bookmarks so each chapter lives in its own file for easier reference.
A lawyer extracts each bookmarked exhibit from a bundled discovery PDF as its own named file.
Only top-level bookmarks are used; nested sub-bookmarks stay inside their parent's file and are not split further.

Frequently asked questions

How is this different from other online PDF tools?: Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.
Are my PDF files uploaded?: No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.
Can I verify that files are not uploaded?: Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.
Does this tool work offline?: Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.
What happens when I refresh the page?: Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.
Does this tool store my files?: No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.
Can this tool unlock password-protected PDFs?: No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.
What technologies does this tool use?: This tool uses pdf.js to read the bookmark outline and client-side JavaScript with pdf-lib to copy each section into its own PDF — your files never leave your browser.
Does this tool use WebAssembly?: No. pdf.js and pdf-lib are plain JavaScript libraries — no WebAssembly is involved. Everything runs in client-side JavaScript within your browser.
How do I split a PDF by its bookmarks?: Choose a PDF that has a bookmark outline using the file picker, then press the split button. The tool reads the top-level bookmarks in your browser, turns each into a page range, and gives you one named download per section.
Why are my chapter sub-sections not split into separate files?: The tool divides the document at its top-level bookmarks, so any nested sub-bookmarks stay inside their parent section's file. Each top-level bookmark runs until the next one begins, which keeps whole chapters intact rather than fragmenting them.
Why did I get an extra file called "Front matter"?: If the document has pages before the very first bookmark, such as a cover or table of contents, those pages are placed in a separate "Front matter" file so no pages are lost. Output files are numbered and named after each bookmark, like "01-Introduction.pdf".
Does Split PDF by Bookmarks cost anything to use?: Split PDF by Bookmarks is completely free — no account, no sign-up, and no cap on how many PDFs you split or how many bookmark chapters each one contains. The tool reads your PDF's outline, divides it into one file per top-level bookmark, and saves every chapter straight to your device, all inside your browser tab; your document is never sent to a server or any external service, and the tool is free and always will be.