Merge PDF

Merging copies the page objects across rather than redrawing them, so the result is not a picture of your documents — it is your documents. Text stays selectable and searchable, vector artwork stays sharp at any zoom, and images are carried over byte for byte. There is no quality setting here because there is no quality decision to make.

That also means the finished file is roughly the sum of its parts. If the result is larger than you want, compressing it afterwards is the separate step, and it is a real one rather than something a merge tool should be doing to your file without asking.

Bookmarks, form fields, the document outline and any embedded attachments are lost. These are structures that point at pages by reference, and carrying them correctly across several documents whose page numbering has just changed is a much harder problem than copying pages — one that tools which claim to do it often get subtly wrong.

Saying so up front is better than letting somebody merge a hundred-page report and discover afterwards that its table of contents no longer goes anywhere. If your documents rely on any of those, merge them in a full PDF editor instead. For the ordinary case — scans, statements, a contract and its annexes, pages that arrived in separate emails — none of it applies.

Look at what people merge: signed contracts, invoices, medical letters, bank statements, application packs with passports in them. It is one of the most sensitive things anybody does with a file, and the usual way to do it is to hand all of the documents at once to a website in exchange for a download link.

Here they never leave your device. You can check that rather than believe it — open the network tab in your browser’s developer tools and watch while you merge, or disconnect from the internet entirely and merge anyway. It works, because the code doing the work is already on your machine.

Files are joined in the sequence they appear in the list, which is the sequence you dropped or picked them in — not alphabetically, and not by the date on the file. Drag a row to move it before merging if the order is wrong.

This is worth checking rather than assuming, because a file manager sorts by name and often hands over `page10` before `page2`. A scanned document split across numbered files is the usual victim, and the mistake is invisible until somebody reads the result.

Nothing is rescaled. A page that was A4 stays A4 and a page that was Letter stays Letter, so merging documents from different sources can produce a file whose pages are not all the same shape.

On screen this is barely noticeable. In print it shows up as one section sitting slightly differently on the paper, or as a printer asking about page size partway through. If the merged file is going to a printer, it is worth scrolling through once at a zoom level where the page edges are visible.

Merging copies the pages across without re-rendering them, so the output is roughly the sum of the inputs and nothing is compressed on the way. Ten scans of five megabytes make a file of about fifty.

That is the honest trade for the quality being untouched. If the merged document is going by email and lands over a size limit, the compression tool on this site is the next step — and running it after the merge rather than on each part is both faster and slightly more effective.