The fastest way to merge PDFs depends on what you have

You can merge two PDF files on Windows, Mac, or a web browser without buying software. The method that works fastest for you depends on whether you want to keep the files in their original order, whether you need to rearrange pages between them, and what device you're using right now.

If you just need to stack one PDF after another in the order they are, a free online tool takes 30 seconds. If you need to pick and choose specific pages from each file or reorder them, desktop software gives you more control. Windows and Mac both have built-in options that cost nothing.

Key Takeaways

  • Online PDF mergers like Smallpdf or ILovePDF let you upload two files and download the combined result in under a minute, with no software to install.
  • Windows users can merge PDFs using Microsoft Edge by opening each file, printing to PDF, and combining them in a folder, or by using free desktop software like PDFtk.
  • Mac users can open PDFs in Preview, drag pages from one file into another, and save the result without leaving the application.
  • If you need to reorder pages or select specific pages from each file, desktop software or online tools with editing features give you that control before you merge.
  • Always keep copies of your original files before merging, in case you need to separate them again later.

Merging PDFs online without installing anything

The simplest route for most people is an online PDF merger. These sites let you upload your two files, arrange them in the order you want, and download the merged result. No account is required, and nothing gets installed on your computer.

Go to Smallpdf.com or ILovePDF.com in your web browser. Click the "Merge PDF" or "Combine PDF" button. Upload your first PDF file by clicking the upload area or dragging the file into it. Then upload your second PDF. The site will show both files stacked in order. If you need to swap their positions, click and drag one file above the other. Click the "Merge" or "Combine" button, wait 10 to 30 seconds, and download the result to your computer.

The trade-off with online tools is that your files travel to someone else's server. If your PDFs contain sensitive information, this method may not be the right choice. Most of these services delete files after a few hours, but read their privacy policy first if you're uncertain.

Merging PDFs on Mac using Preview

Mac's built-in Preview application can merge PDFs without any extra software. Open the first PDF file in Preview (right-click the file, select "Open With," and choose Preview). Go to the menu bar and click "View," then select "Thumbnails" to see a sidebar showing all pages in the current file.

Open your second PDF file in a separate Preview window (File > Open, or Command+O). In the second window, click View > Thumbnails again. Now you'll see thumbnails of the second PDF's pages. Click and drag any page from the second window's thumbnail panel into the thumbnail panel of the first window. The pages will insert in the order you drag them. When you're done, go to File > Save in the first window to save the merged result.

If you want to reorder pages after merging, you can drag them around in the thumbnail panel before saving. This method keeps everything on your computer and gives you full control over page order.

Merging PDFs on Windows using Microsoft Edge

Windows 10 and 11 include Microsoft Edge, which can open and print PDFs. Open your first PDF in Edge. Go to the three-dot menu in the top right, click "Print" (or press Ctrl+P), and in the printer dropdown select "Print to PDF." Choose where to save the file and click "Save." Repeat this step for your second PDF, saving it with a different name.

This method creates two separate PDF files, so you'll need a second step to actually combine them. Download and install PDFtk Free (pdftk.com), a free command-line tool. Open Command Prompt (search "cmd" in the Windows search bar), navigate to the folder where you saved your two PDFs, and type: pdftk file1.pdf file2.pdf cat output merged.pdf (replacing file1, file2, and merged with your actual file names). Press Enter, and the merged PDF will appear in the same folder.

This route is more technical than the Mac method, but it keeps everything on your computer and costs nothing.

Using free desktop software for more control

If you need to pick specific pages from each PDF or reorder them before merging, desktop software gives you a visual way to do this. PDFtk, Ghostscript, and LibreOffice Draw are all free and work on Windows and Mac.

LibreOffice Draw is the most user-friendly option. Download and install it from libreoffice.org. Open LibreOffice Draw, go to File > Open, and select your first PDF. The PDF will open as a series of pages you can see and click on. Go to Insert > Page from File, select your second PDF, and choose which pages to insert and where. You can drag pages around to reorder them. When you're satisfied, go to File > Export as PDF to save the merged result.

This method takes a few minutes longer than online tools, but you have complete control over which pages go where, and your files never leave your computer.

What to do if the merged file doesn't look right

Sometimes a merged PDF has pages in the wrong order, or one file's pages are much larger or smaller than the other's. If pages are in the wrong order, go back to your original files and merge them again in a different sequence. If page sizes don't match, open the merged file in Preview (Mac) or Adobe Reader (Windows or Mac), and the viewer will usually scale them to fit.

If the file is corrupted or won't open after merging, the original PDFs may have been damaged. Try merging them again using a different method. If the problem persists, the original files may not be readable, and you may need to recreate them from their source documents.

Always keep your original PDF files until you've confirmed the merged version is correct and usable. Once you're certain the merge worked, you can delete the originals if you want to save space.

Frequently Asked Questions

Can I merge more than two PDFs at once?

Yes. Online tools like Smallpdf and ILovePDF let you upload three or more files and merge them all in one step. Desktop software like LibreOffice Draw also handles multiple files. The process is the same: upload or open all the files, arrange them in the order you want, and merge.

Will merging PDFs reduce the file quality?

No. Merging simply combines the files without re-compressing them. The quality of each page stays the same as the original. The merged file will be slightly larger than either original file because it contains both sets of pages.

What if one PDF is password-protected?

You'll need to remove the password before merging. Open the protected PDF in Adobe Reader or Preview, enter the password when prompted, then save it as a new file without password protection. After that, you can merge it with other PDFs using any method.

Can I undo a merge if I change my mind?

No. Once you save a merged PDF, the original files are separate. If you need to separate them again, you'll have to manually extract pages from the merged file using Preview, Adobe Reader, or an online tool. This is why keeping copies of your original files is important.

Is it safe to use online PDF mergers with confidential documents?

Online tools send your files to a server you don't control. If your PDFs contain sensitive information like financial records or medical details, use a desktop method instead. Preview on Mac and LibreOffice Draw on Windows both work entirely on your computer with no internet upload.