How to combine several PDFs into one file

Combining PDFs is one of those tasks that is trivial once and irritating weekly. This covers doing it quickly in a browser, doing it without any tool on Mac and Windows, and the two things that usually go wrong.

The fastest way: in your browser

Our merge PDF tool runs entirely on your device — nothing is uploaded, which matters when you are combining contracts, invoices, or medical records.

1. Open merge PDF.
2. Select every file you want to combine. You can add them all at once.
3. Drag them into the order you want. The order in the list is the order in the document — this is the step people skip and then redo.
4. Merge, and save the result.

Because the work happens locally, it is quick, and it stays quick on large files where an upload-based tool would have you waiting twice.

Without any tool

On a Mac, Preview will do it. Open the first PDF, show the sidebar (View → Thumbnails), then drag the other PDF files into the sidebar where you want them to land. Export the result via File → Export as PDF. Use Export, not Save, or you will edit the original in place.

On Windows, there is no built-in merge. The genuinely free options are LibreOffice Draw, which handles one file at a time and is fiddly, or the browser method above. Windows’ “Microsoft Print to PDF” does not combine existing PDFs — a common and frustrating dead end.

On a phone, the Files app on iOS can do it: select several PDFs, long-press, and choose Create PDF. On Android it depends heavily on the vendor’s file manager, and the browser method is usually less trouble.

Getting the order right

Two rules cover almost every case.

File name order is not merge order. Most tools merge in the order files appear in the list, which reflects how you selected them, not their names. Check the list before merging.

Files named 1, 2, … 10 sort wrongly. Alphabetical sorting puts 10 immediately after 1, so a batch named page1 through page12 ends up scrambled. If you control the names, zero-pad them: page01, page02. This costs nothing and saves the problem entirely.

If a merged document has ended up out of order, you do not need to redo the merge — open it in organize PDF and drag the pages into place.

Combining things that are not PDFs

Photos and scans. Convert them first with JPG to PDF, which can turn a batch of images into a single document in one step — the usual answer for “I photographed six receipts and need one file.”

Word or Excel documents. Export each to PDF from its own application (File → Save As → PDF, or Print → Save as PDF), then merge. Converting first gives a far more reliable result than any tool that promises to merge mixed formats directly.

When the merged file is too large

Merging adds sizes together, so a set of scans that were individually fine can produce something that will not send.

Before compressing, check whether the file needs to be smaller or simply shorter. If the recipient needs a subset, split it and send only the relevant pages.

If it genuinely needs to be smaller, compress it — but note that merged scans compress well, while merged text documents barely compress at all. Our guide on reducing PDF file size explains which case you are in and what to expect.

One thing worth knowing: merging does not itself add much overhead. If three 2 MB files produce a 6 MB result, nothing has gone wrong. If they produce 20 MB, something was re-encoded along the way, and the tool that did it was not a good one.

A note on privacy

The documents people merge are disproportionately sensitive — contracts, tax returns, medical records, applications. Most online merge tools upload every file to a server, process it there, and rely on you trusting their retention policy.

That trade is unnecessary for this task. A browser can merge PDFs perfectly well on its own, which is how our tool works: your files are read into memory on your device, combined there, and saved from there. Nothing is transmitted, so there is no retention policy to trust.