Merge PDF files
Combine several PDFs into one document, in your browser. Nothing is uploaded.
- Runs on your device — the file is never sent anywhere
- No sign-up, no watermarks, no daily quotas
- Free, with no limit on how often you use it
How it works
Merging PDFs is the single most common thing people need a PDF tool for, and it is also the one most likely to involve documents you would rather not hand to a stranger — signed contracts, invoices, scanned identity documents, medical letters. This one never receives them: the merge happens inside this page, using your own computer.
What actually happens to the pages
Each source document is parsed, its pages are copied into a new document in order, and the result is written back out. Page content, embedded fonts and images are carried across unchanged — nothing is re-rendered or re-compressed, so there is no quality loss whatsoever.
Order and size
Files merge in the order they appear in the list. The combined file is roughly the sum of its parts, because PDF pages are copied rather than recompressed. Merging ten 2 MB documents gives you roughly a 20 MB document.
What it does not do
Form fields, annotations and digital signatures may not survive a merge intact — signatures in particular are invalidated by design the moment a signed document is altered, in any tool. If a document is signed and the signature must remain valid, do not merge it.
Merge PDF files — questions
Is there a limit on how many PDFs I can merge?
No fixed limit. The practical constraint is your device's memory, since every document is held in the page while it is combined. Dozens of ordinary documents are fine.
Are my PDFs uploaded anywhere?
No. The merge runs entirely in your browser using pdf-lib. No copy of your document is transmitted to us or to anyone else.
Does merging reduce quality?
No. Pages are copied across without being re-rendered or recompressed, so the result is identical to the originals.