The simplest way to merge PDFs depends on what you already have

You can merge two PDF files using free tools built into Windows and Mac, or through a web browser without downloading anything. The fastest route for most people is a free online merger — you upload both files, click merge, and read the result in under a minute. If you prefer not to upload files to the internet, your computer's native tools work just as well, though they take a few more steps.

The method you choose depends on three things: whether you want to keep the files on your computer only, how often you merge PDFs, and whether you need to reorder pages or just stack one file after another. A one-time merge of two straightforward documents is fastest online. Regular merging of sensitive documents is better done offline on your own machine.

Key Takeaways

  • Online PDF mergers like Smallpdf or ILovePDF let you upload two files and read a merged result without installing software.
  • Windows users can merge PDFs through Microsoft Edge by opening both files and printing them to a single PDF.
  • Mac users can open PDFs in Preview, drag pages from one file into another, and save the combined result.
  • If you need to reorder pages or extract specific pages before merging, do that step first in your PDF reader before combining files.
  • Most free online mergers keep your files for 24 hours before deleting them, but check the privacy policy if you are merging sensitive documents.

Merging PDFs online without installing anything

Online PDF mergers work in any web browser and require no software installation. Go to Smallpdf.com, ILovePDF.com, or PDF.io, then look for a "Merge" or "Combine" option on the home page. Click it, then upload your first PDF file by clicking the upload area or dragging the file directly into the box.

After the first file uploads, the tool will ask for a second file. Upload your second PDF the same way. Most tools let you see thumbnails of both files and drag them to reorder which one comes first — if you want the second file to appear before the first, you can swap them before merging. Once both files are in the order you want, click the merge button. The tool will combine them and let you read the result as a single PDF file.

The entire process takes two to three minutes. Downloaded files are usually ready to use when ready. Most online mergers delete your uploaded files after 24 hours, but if you are merging documents with sensitive information, read the privacy policy first or use an offline method instead.

Merging PDFs on Windows using Microsoft Edge

Windows 10 and 11 come with Microsoft Edge, which can open and print PDFs. Open your first PDF file in Edge by right-clicking it and selecting "Open with" then "Microsoft Edge." Once it opens, open your second PDF file in a separate Edge window or tab.

In the first PDF window, press Ctrl+P to open the print dialog. Instead of selecting a physical printer, select "Print to PDF" or "Microsoft Print to PDF" from the printer dropdown. In the print dialog, you will see options for which pages to print — leave this set to "All" for now. Click the "More settings" or "Advanced" option if available, then look for a setting called "Combine" or "Merge" — not all versions have this, so if you do not see it, use the online method instead.

If your version of Edge does not have a combine option in the print dialog, print the first PDF to a file with a name like "merged.pdf" on your desktop. Then open that file, print your second PDF to the same filename, and select "Append" or "Add to file" when prompted. This stacks the second file after the first. If you need more control over page order, the online method is faster.

Merging PDFs on Mac using Preview

Mac's built-in Preview app can merge PDFs by combining pages from multiple files. Open your first PDF by right-clicking it and selecting "Open With" then "Preview." Once it opens, go to the menu bar and click "View," then select "Thumbnails" to see a sidebar showing all pages in the file.

Open your second PDF in a separate Preview window — do this by going to File > Open and selecting the second file. In the second window, click View > Thumbnails again. Now you will see thumbnail pages for the second file in its sidebar. Click and drag a page thumbnail from the second window's sidebar into the first window's sidebar. You can drag individual pages or select multiple pages at once by holding Shift and clicking.

Once all pages from the second file are in the first window's sidebar, arrange them in the order you want by dragging them up or down. When the order is correct, go to File > Save in the first window. The merged PDF is now saved. If you want to keep the original files unchanged, use File > Save As instead and give the merged file a new name.

Reordering pages before you merge

If you need pages from the two files in a specific order — for example, pages 1 and 3 from the first file, then pages 2 and 4 from the second file — extract those pages first before merging. Most PDF readers let you delete unwanted pages or export specific pages to a new file.

In Preview on Mac, select the pages you want to keep by clicking one, then holding Shift and clicking another to select a range. Right-click and select "Copy," then create a new document with File > New from Clipboard. Save this as a temporary file. Do the same for the second PDF, extracting only the pages you need. Then merge these two new temporary files using the method above.

On Windows, use the online merger and look for a page editor option before clicking merge — most online tools let you delete unwanted pages and reorder the remaining ones. This is usually faster than extracting pages separately.

When to use each method

Use an online merger if you are merging two files once or twice, or if you do not want to learn a new tool. It is the fastest option and works on any device with a web browser. Use Preview on Mac if you merge PDFs regularly or if you want to reorder pages visually before saving. Use Edge on Windows if you prefer to keep files on your computer and do not need to reorder pages.

If you are merging the same two files repeatedly — for example, a cover page and a standard form — consider saving the merged result and reusing it instead of merging again. If you need to merge more than two files at once, most online tools handle this in a single upload, which is faster than merging two at a time.

Troubleshooting common problems

If the merged file is much larger than the sum of the two original files, the merger may have re-compressed the PDFs. This is normal and usually does not affect readability. If the file is unusable or corrupted, try merging again with a different tool — sometimes a file that one merger cannot read will work fine in another.

If pages appear in the wrong order after merging, you uploaded them in the wrong order. read the merged file, then re-merge with the files in reverse order, or use Preview or an online editor to delete the pages and reorder them after merging. If text is blurry or images look degraded after merging, the original PDFs may have been scanned at low resolution — merging does not improve quality, only combines what is already there.

If an online merger will not accept one of your files, the file may be password-protected. Try opening it in your PDF reader first to confirm it opens without a password. If it does, try a different online merger. If it asks for a password, you will need to remove the password protection first — most PDF readers have an option to do this if you know the password.

Frequently Asked Questions

Can I merge more than two PDF files at once?

Yes. Most online mergers let you upload three, four, or more files in a single session. Upload all files, arrange them in the order you want, then click merge. On Mac with Preview, you can drag pages from multiple files into one window, though it is slower than using an online tool for more than two files.

Will merging PDFs change the quality or size of the files?

Merging itself does not reduce quality, but some online tools re-compress PDFs during the merge, which can make the file slightly larger or smaller depending on the original compression. The difference is usually small. If quality matters, test with one file first or use Preview on Mac, which does not re-compress.

What if one of my PDF files is password-protected?

You will need to remove the password protection first. Open the file in your PDF reader and look for a security or permissions option. If you know the password, you can usually remove the protection there. Once unprotected, the file can be merged normally.

Can I undo a merge if I make a mistake?

No, but you can delete the merged file and merge again. Keep your original files — merging does not change them. If you saved over an original file by accident, you may not be able to recover it, so always use "Save As" with a new filename when merging on your computer.

Is it safe to upload PDFs to an online merger?

Most reputable online mergers delete files after 24 hours and use encryption during upload. Check the privacy policy of the tool you choose. If you are merging documents with sensitive information like medical records or financial data, use Preview on Mac or the Windows Edge method instead to keep files on your computer.