Merge PDFs

How many files can I merge at once?

There is no hard limit. In practice, very large files may be constrained by your device's available memory since all processing happens in the browser.

Will the page order match the list order?

Yes. Pages from each file are appended in the order shown in the list. Drag a row to change file order before merging.

Can I merge password-protected PDFs?

Yes, if you know the password. HerePDF asks for it when you add the file and merges an unlocked copy (the result is not password-protected). A file that opens freely but blocks editing (an owner password) can't be merged: if it's your document, save an unprotected copy from your PDF reader or re-export it without the security setting; otherwise ask whoever sent it for an unrestricted copy.

Does merging affect image or text quality?

No. HerePDF re-assembles the pages without re-encoding any content, so image quality and text fidelity are fully preserved. Fillable form fields do not carry over, though: they keep their appearance but are no longer fillable in the merged file.

What happens to bookmarks when I merge?

They are kept. Each file's bookmarks are carried over and point at the right pages of the merged file, nested under one bookmark named after the file (untick "Add a bookmark for each file" to keep them in one flat list). A bookmark's colour or bold/italic style is not kept, and neither is a bookmark that opens a file or runs a script; the result tells you how many. You can change the bookmarks afterwards with the Bookmarks tool.