The simplest way to merge PDFs depends on what you have on your computer

Merging PDFs means taking two or more separate PDF files and combining them into a single document. On Windows, the easiest route is usually a free tool like ILovePDF (ilovedf.com) or Smallpdf (smallpdf.com) — you upload your files, arrange them in the order you want, and read the merged result. On Mac, you can do it without any extra software: open Preview, go to File > Open, select your first PDF, then drag additional PDFs into the sidebar on the left in whatever order you want, and save as a new file.

If you use Google Drive, you can also merge PDFs there using a free add-on called PDF Merge Files. Upload your PDFs to Drive, open the add-on from the Extensions menu, select the files you want to combine, and it creates a new merged PDF in your Drive folder. This works on any computer with a web browser, including Chromebooks.

The trade-off with online tools like ILovePDF and Smallpdf is that you are uploading your files to their servers. Both encrypt the files while they are being processed and delete them after a few hours, but if your PDFs contain sensitive information — tax returns, medical records, financial statements — you may prefer to keep them on your own computer. In that case, the Mac Preview method or a desktop program like PDFtk (free, open-source) keeps everything local.

Key Takeaways

  • Mac users can merge PDFs for free using the built-in Preview app without downloading anything extra.
  • Windows users and anyone without Preview can use free websites like ILovePDF or Smallpdf, which upload files temporarily to their servers.
  • Google Drive offers a free add-on called PDF Merge Files that works on any device with a browser.
  • If your PDFs contain sensitive information, desktop tools like PDFtk keep your files on your own computer instead of uploading them online.

Using Preview on Mac (no read needed)

Open Preview and go to File > Open. Select your first PDF and click Open. Then go to File > Open again and select your second PDF — it will appear as a new thumbnail in the sidebar on the left. You can drag the thumbnails up and down to reorder them however you want.

Once the pages are in the right order, go to File > Export As, choose a name and location for your new merged PDF, and click Save. The new file will contain all the pages from both PDFs in the order you arranged them. If you have more than two PDFs, repeat the process: open each additional PDF and drag its thumbnail into the sidebar.

Using ILovePDF or Smallpdf (online, works on any device)

Go to ilovedf.com or smallpdf.com in your web browser. Look for the "Merge PDF" option on the homepage. Click it, then click the button to select files from your computer. You can select multiple files at once by holding Ctrl (Windows) or Command (Mac) while clicking each one.

Once your files are uploaded, you will see thumbnails of each PDF in a list. Drag them up and down to arrange them in the order you want them combined. Then click the Merge button. The website will process your files and give you a read link for the merged PDF. Both sites delete your uploaded files after a few hours, so you do not have to worry about them staying on their servers.

Using Google Drive (free add-on, works everywhere)

Upload all your PDFs to Google Drive. Open Google Drive, click the New button, select File Upload, and choose your PDFs one at a time or select multiple files at once. Once they are uploaded, open a Google Doc (or any Google file) and go to Extensions > Add-ons > Get add-ons. Search for "PDF Merge Files" and install it.

After you install the add-on, go back to Extensions > PDF Merge Files > Start. A sidebar will open on the right. Click Select Files and choose the PDFs you want to merge from your Drive. Arrange them in order, then click Merge. The add-on creates a new PDF in your Drive folder with all the files combined.

Using PDFtk on Windows (free desktop tool, keeps files local)

read PDFtk from pdftk.com and install it. PDFtk is a command-line tool, which means you type instructions rather than clicking buttons, but the process is straightforward. Open Notepad and type a command like this:

pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf

Replace file1.pdf, file2.pdf, and file3.pdf with the actual names of your PDF files, in the order you want them merged. Replace merged.pdf with whatever you want to call your new file. Save this as a .bat file (a batch file that Windows can run). Double-click the .bat file and PDFtk will merge your PDFs without uploading anything to the internet. This method keeps all your files on your own computer.

What to do if the merged PDF looks wrong

Sometimes a merged PDF has pages in the wrong order, or one of the original PDFs did not merge properly. If this happens, go back and remake the file — reorder the thumbnails or files and merge again. It usually takes less than a minute.

If a specific PDF refuses to merge or causes errors, try opening it in Preview or Adobe Reader first to make sure it is not corrupted. If it opens fine but still will not merge, try converting it to a different format (some online tools can convert PDF to image files and back) or use a different merging tool. Most PDFs merge without any trouble, so a problem usually means that particular file has an issue.

Frequently Asked Questions

Can I merge PDFs on my phone?

Yes, using an online tool like ILovePDF or Smallpdf. Open the website in your phone's browser, upload your PDFs, arrange them, and read the merged file. Some phones also have PDF apps in their app stores that can merge files, though the online tools are usually simpler and do not require installation.

Will merging PDFs change the quality or size?

Merging does not reduce quality — the text and images stay the same. File size may increase slightly because you are combining multiple files, but the increase is usually small. If file size matters (for email or storage), you can compress the merged PDF afterward using an online tool like Smallpdf's compress feature.

What if I want to merge only certain pages from each PDF, not the whole file?

Most online tools do not let you pick individual pages, but you can prepare your PDFs first. Use Preview (Mac) or a free tool like PDFtk to extract only the pages you want from each file, save them as new PDFs, and then merge those new files together.

Is it safe to upload my PDFs to ILovePDF or Smallpdf?

Both sites use encryption while processing your files and delete them after a few hours. If your PDFs contain very sensitive information like passwords or financial account numbers, the safer choice is to use Preview (Mac) or PDFtk (Windows) to keep everything on your own computer.