Merge PDFs and Keep the Bookmarks
Combining PDFs usually destroys their bookmarks — pages get copied, the outline gets left behind, and a navigable document becomes a flat one. This merge reads each file's outline first, shifts it onto the pages it ends up occupying, and writes the whole tree back out. Files with no bookmarks of their own still get one, so every part of the result is reachable from the bookmark panel.
Drag PDFs here, or click to browse
Processed locally — never uploaded
Bookmark structure
Why other mergers lose your bookmarks
A PDF's bookmarks are not attached to its pages. They live in a separate outline tree in the document catalog, and each entry points at a page by reference. Copy the pages into a new document and those references have nothing to resolve against, so a plain copy-pages merge produces a document with no outline at all — not as a bug, but as the default behaviour of the operation. Some tools do handle this; many of the fastest, most popular ones do not.
Preserving them means reading each source's outline before the copy, tracking where every page lands in the combined document, rewriting each entry's target, and building a fresh outline tree at the end. That is what this page does, and it is why the result opens with a bookmark panel that reflects everything you put in.
Questions
- Do the bookmarks survive the merge?
- Yes — that's the point of this tool. A plain copy-pages merge drops every bookmark, because bookmarks live in the document catalog and point at pages by reference, not on the pages themselves; copy the pages and those references have nothing left to resolve against. Here each file's outline is read before its pages are copied, its page numbers are shifted to where they land in the combined document, and the whole tree is rewritten into the output.
- What happens to a file that has no bookmarks?
- It still gets one bookmark, named after the file, pointing at its first page. Otherwise those pages would be unreachable from the bookmark panel and the merged document would be navigable only in parts.
- Can I control how the bookmarks are nested?
- Two shapes. 'One entry per file' nests each source's bookmarks under a top-level entry named for the file — right when you're combining separate documents. 'Flat' splices each file's bookmarks straight in at the top level, for when the inputs are chapters of one document and a per-file wrapper would just add noise.
- Can it add a table of contents page as well as bookmarks?
- Yes. Tick 'Add a printed contents page' and the merge renders a clickable table of contents from the combined outline — one row per file and per carried bookmark, each linking to its page — at the front or the back of the document. It's the same renderer the Bookmarks-to-TOC tool uses, so the result matches what that tool produces from a single file.
- Are my files uploaded anywhere?
- No. pdf-lib does the merge in your browser; the files never leave your machine. That also means very large merges are bounded by your own memory rather than by an upload limit.
- Can I reorder files before merging?
- Yes — the queue is the output order, and each row moves up or down. You can also rename the bookmark each file gets, which defaults to the file name without its extension.