How to Merge PDF Files on Windows & Mac

By Nathan Hays · Updated July 31, 2026

Two contracts that need to be one attachment. A cover letter and a résumé. Twelve scanned receipts for one expense report. Combining PDFs is one of the most common document jobs there is. Here are the three best free ways to do it, on any computer.

Method 1: In your browser (works on Windows, Mac, and Chromebooks)

1. Scroll up to the merge tool on this page (or open the full Merge PDF tool).
2. Drag your PDF files in (or click to browse). Add as many as you need.
3. Drag the files into the order you want (or use the up and down arrows).
4. Click Merge and download your single combined PDF.

Because the merge runs locally with in-browser processing, it's private by design (contracts, statements, and IDs stay on your machine) and there's no upload wait, no sign-up, and no watermark.

What you see along the way

Every file you add becomes a row showing its name, its size, and how many pages it holds. That page count is the single most useful thing on the screen: it is how you notice that you grabbed the six-page draft instead of the eight-page final before you send the result to somebody, rather than after. Rows can be dragged into any position, nudged one place at a time with the up and down arrows, or thrown out with the × on the right.

The button underneath counts the files it is about to combine, and stays disabled until there are at least two of them. That minimum is the only rule the tool enforces: there is no cap on how many files you add, no page limit, and no daily quota. While it works, a progress line names the file it is currently adding, which is worth watching on a long batch because it tells you where a slow file is. When it finishes you get three numbers, the file count, the total page count, and the size of the result, and then a download button that saves the file the way any other download saves.

The result arrives named merged.pdf. Rename it to something a recipient will recognize before you attach it anywhere.

Getting the order right

Order is simply the order of the rows, top to bottom. Files land in the list in the order you added them, which is not always the order you meant, especially when you select a whole folder at once and the operating system hands them over alphabetically. Dragging is quickest on a mouse; the arrow buttons are easier on a touchscreen, where a drag can be mistaken for a scroll.

One helpful behavior: if you have already merged and then change the order, the finished result is cleared away. That is deliberate. It means the download button on screen always belongs to the arrangement you are looking at, so you can never hand somebody yesterday's arrangement by accident. Reorder freely, then press Merge again.

What the merge actually does to your files

Under the surface this is a copy, not a re-print. The tool creates an empty PDF and copies every page of each source file into it in order, so what goes in is what comes out: text stays real text that can be selected and searched, images keep the data they arrived with, and each page keeps its own dimensions and rotation. Mixed page sizes in a merged file are normal for that reason. A letter-size cover page followed by A4 pages stays exactly that, and each page still prints at its own size.

What a page copy does not bring along is the document-level furniture that lives outside the pages themselves. If your originals carried a bookmark outline, fillable form fields, file attachments, or a contents page built from internal links, treat those as things to check in the merged file rather than things to assume. For the documents people actually merge most, scans, statements, contracts, invoices, and reports, the question never comes up.

Nothing here re-compresses, downsamples, or re-renders anything, which is why a merged file weighs roughly what its parts weighed together, and why the quality of the result is identical to the quality of the originals.

Merging only some of the pages

The merge tool takes whole files. Add a 40-page report and all 40 pages go in; there is no range box on this screen. The job divides cleanly in two instead, and either half can come first.

Trim, then merge: run each file through the Split PDF tool, keep the pages you want, and merge the trimmed copies. Merge, then trim: combine everything here first, then open the result in Split PDF, where you can click page thumbnails or type a range such as 1-3, 7 and save what you keep as a single new document. The second route is usually less work, because you only have to think about page numbers once, on a document whose numbering is already final. Both steps copy pages rather than redraw them, so a round trip through the pair costs you nothing in quality.

Method 2: On a Mac, Preview is built in

macOS ships with a real PDF combiner hiding in Preview:

1. Open the first PDF in Preview.
2. Choose View → Thumbnails so the page sidebar appears.
3. Drag the second PDF file from Finder straight into the sidebar, at the position you want its pages.
4. Reorder pages by dragging thumbnails; delete any you don't need.
5. Choose File → Export as PDF… to save the merged file.

One caution: saving in place can overwrite your original, so export a copy instead.

Method 3: On Windows, the honest answer

Windows 10 and 11 have no built-in way to merge PDFs. The commonly suggested workaround (opening files in Edge and using Print → Microsoft Print to PDF) technically produces a combined file, but it re-renders every page: text can blur, links and bookmarks are stripped, and file size often balloons. It's fine in a pinch; it's not what you want for anything that matters.

Your practical options on Windows are a browser-based merger (Method 1, nothing to install) or a desktop app like PDFsam Basic (free, open source) if you regularly merge very large batches offline.

When something goes wrong

Most merge problems announce themselves clearly. Here is what each message means and what to do about it.

• A file was skipped. Only PDFs go into a merge, so anything else you dropped in is set aside and counted in a short notice. Convert images first with Images to PDF, then merge that PDF with the rest.
• "Could not be read. It may be corrupt or password-protected." A file that asks for a password before it opens cannot be merged. Open it in your usual PDF viewer with the password, save an unprotected copy, and merge that copy. If there is no password, the file itself is damaged; re-download or re-export it from wherever it came from.
• A row shows no page count. The count is read when the file is added, and a blank one means the file could not be opened for counting. It will usually fail at merge time too, so treat a blank count as an early warning and check that file before you go further.
• The button says to add at least 2 PDFs. A merge needs two files. If you are trying to reorder or remove pages inside a single document, that is Split PDF, not merge.
• The pages came out in the wrong order. The result follows the row order exactly, so reorder the rows and press Merge again. The previous download clears itself as soon as you change anything, which is your signal that a new one is needed.
• The merged file is enormous. Merging adds sizes together and does not compress anything. Run the result through Compress PDF once at the end, and see why PDFs get so large if the number still looks wrong.
• The tab struggles on a very large batch. Everything happens in your browser using your own memory, so a huge stack of scans can be a lot to hold at once. Merge in two passes, halves first and then the two halves together, or work on a computer instead of a phone.

Before you send a merged file, open it once and skim the seams where documents join. Confirm the total page count matches what you expected, and that nothing landed upside down; if a page did, Rotate PDF fixes it without touching quality.

A word on the print-to-PDF route

Every major browser can print a document to a PDF file instead of to paper, which is why the print dialog gets suggested so often in answers to this question. It is a real way to produce a PDF and a fine way to save a web page. As a merging technique it is a last resort, because printing re-renders the pages instead of copying them, with the consequences described in Method 3. If you have any other option available, take it.

Which method should you use?

Frequently asked questions