How to merge PDFs without losing bookmarks or hyperlinks
The default merge in most tools strips bookmarks. Here's how to keep them — and reconcile internal links to the new page numbers.
Merging PDFs is one of the most common operations on this site, and most of the time it just works. The corner case people hit is that the merged file loses its bookmarks — the side-panel navigation outline that lets you jump to chapters or sections. If your inputs were chapters of a book or sections of a report, that side panel is the entire reason you wanted a single document instead of multiple. Losing it defeats the purpose.
Why bookmarks disappear during a bad merge
Cheap merge implementations concatenate page streams and write a fresh document with no outline. Bookmarks are a separate structural feature of the PDF format — pointers that say 'this title goes to that page'. They live in the document's outline tree, not in the page content. If the merge tool only copies pages, the outline tree gets thrown away.
How a proper merge handles them
When you merge with pdfcraft ai's free Merge tool, we copy the outline trees from each input and rewrite their page references to point into the merged document. Bookmark text stays the same; only the page numbers shift. Internal hyperlinks that pointed to a different page within the same source PDF get reconciled the same way — they now land on the correct page in the merged output. External hyperlinks (to web URLs) survive untouched because they don't depend on page numbers.
What you need to do
Nothing different from a normal merge. Drop in your PDFs, drag thumbnails to set the order, click Merge. The bookmark reconciliation happens automatically. Open the result in any PDF reader and you should see the combined outline in the side panel — chapter names from each input, in source order, with the right pages.
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