Merge PDF

Combine any number of PDF files into a single document. The order in the list is the order in the result, and everything happens inside this browser tab.

What merging actually does

The pages of each input document are copied into a new document in sequence, carrying their content, fonts and images with them. Page sizes are preserved individually, so a landscape scan sandwiched between two portrait pages stays landscape rather than being stretched.

This is a structural operation rather than a re-render. The pages are not rasterised, so text stays selectable and searchable and vector graphics stay sharp.

Order is explicit, not alphabetical

Files appear in the list in the order you added them, and each one can be moved up or down before merging. This matters because scanner output and download folders name files in ways that rarely match the order you want.

Adding the same file twice is allowed and sometimes useful — a cover page repeated between sections, for example.

What does not survive a merge

Interactive form fields, digital signatures and document-level bookmarks are the usual casualties. A signature in particular is a cryptographic assertion about one specific file; producing a new file necessarily invalidates it. That is not a defect of any given tool — it is what a signature is for.

If you need signed documents to stay verifiable, keep them separate and send them alongside the merged file rather than inside it.

Encrypted documents

PDFs that are merely restricted — the kind that discourage printing or copying without asking for a password to open — are handled. PDFs that require a password before they can be opened at all cannot be merged until you remove that protection first, because the content genuinely cannot be read without the key.

Nothing is uploaded

Merging is done by pdf-lib running in your browser. This is worth pausing on: the documents people merge are contracts, bank statements, medical records and identity papers. Every other popular merge tool uploads all of them to a server.

There is no file count limit, no size cap, no watermark and no account, because the work costs us nothing. Watch the DevTools Network tab while you merge and you will see nothing carrying your documents.