How to Merge Multiple PDF Files Into One on Mac

The fastest way: use Preview to combine PDFs without extra software

macOS comes with Preview, an app already on your Mac that can merge PDFs in under a minute. You do not need to read anything or pay for a subscription. Open Preview, drag your PDF files into it in the order you want them, then export as a single PDF. This works for any number of files and produces a clean result.

The reason Preview works so well for this task is that it treats each PDF as a document you can edit — you can rearrange pages, delete pages you do not want, and combine multiple files all in one window. For most people combining a few PDFs, this is the only tool you will ever need.

Key Takeaways

Preview, which comes free on every Mac, can merge multiple PDFs by opening them and exporting them as a single file.
You control the order of your PDFs before merging, so you can arrange them the way you want without editing after.
The process takes about two minutes and produces a file you can when ready use or share.
If you need to merge PDFs regularly as part of your work, a dedicated PDF tool may save time, but Preview handles occasional merging without cost.

Step-by-step: merging PDFs in Preview

Start by opening Preview. Click the Finder icon in your dock, then Applications, then double-click Preview. The app opens with a blank window.

Now open your first PDF. Go to File > Open, navigate to the folder where your PDFs live, and select the first file you want in your merged document. Click Open. The PDF appears in Preview.

Next, you will add the other PDFs to this same window. Go to File > Open again and select your second PDF. This time, Preview asks whether you want to open it in a new window or add it to the current one. Click "Open in the same window." Repeat this step for each PDF you want to merge, always choosing "Open in the same window."

As you add PDFs, Preview shows them as a list of thumbnails on the left side of the window. You can drag these thumbnails to rearrange them — if your second PDF should actually come third, just drag its thumbnail down. This is where you control the final order of your merged file.

Once all your PDFs are in Preview and arranged the way you want, go to File > Export. Choose a name for your merged PDF, pick a location to save it (your Desktop or Documents folder is usually easiest), and click Save. Preview combines all the files into one PDF and saves it.

What to do if Preview opens PDFs in separate windows

Older versions of macOS sometimes open each PDF in its own window instead of adding it to the current one. If this happens to you, you can still merge them — it just takes one extra step.

Open your first PDF in Preview as described above. Then open your second PDF normally (it will open in a new window). In the second window, select all the pages by pressing Command+A, then copy them with Command+C. Switch back to your first PDF window, click at the end of the page list on the left, and paste with Command+V. Repeat for each additional PDF. Then export as one file.

This method is slightly slower than the "Open in the same window" approach, but it works on any Mac and produces the same result.

Arranging pages and removing ones you do not want

Before you export, you can clean up your merged PDF. If one of your source PDFs has a blank cover page or a page you do not need, you can delete it. Right-click the thumbnail on the left side and select Delete, or click the thumbnail and press Delete on your keyboard.

You can also rearrange individual pages, not just whole PDFs. If page 3 of your second PDF should come before page 2, drag that single thumbnail to the right spot. This is useful when you are combining documents that were originally separate and need to be reordered to make sense together.

Once your merged PDF looks the way you want — all pages in the right order, unwanted pages removed — export it as described above. Preview saves your changes into the new file without touching the original PDFs.

When to use a dedicated PDF tool instead

Preview handles merging well, but it has limits. If you merge PDFs several times a week as part of your regular work, a dedicated PDF tool like PDFtk, Automator, or a paid service like Adobe Acrobat may save you time. These tools let you set up a workflow you can repeat without opening windows each time.

Dedicated tools also offer features Preview does not — compressing file size, adding passwords, extracting specific pages from multiple PDFs and combining only those, or merging on a schedule. If you need any of these features, Preview is not the right choice.

For occasional merging — combining a few PDFs once a month or less — Preview is faster than learning a new tool and costs nothing.

Troubleshooting: when the merged PDF does not look right

If your exported PDF has pages in the wrong order, you did not arrange the thumbnails correctly before exporting. Open the merged PDF in Preview again, rearrange the pages the way you want, and export it as a new file. The original PDFs are unchanged, so you can try again without losing anything.

If the file size is much larger than you expected, Preview may have compressed the images differently than your original PDFs. This is usually not a problem — the file still works and prints normally. If you need the exact same file size, check whether your original PDFs were already compressed, and consider using a tool designed for compression instead.

If Preview crashes or freezes while you are working with very large PDFs (over 500 MB each), your Mac may not have enough memory. Close other apps to free up space, or break your merge into smaller batches — merge PDFs 1 through 5, then merge that result with PDFs 6 through 10.

Frequently Asked Questions

Can I merge PDFs on Mac without Preview?

Yes. Automator, another free Mac app, can merge PDFs if you set up a workflow. You can also use command-line tools like ImageMagick or Ghostscript if you are comfortable with Terminal. For most people, Preview is simpler because it has a visual interface and requires no setup.

Does merging PDFs in Preview change the original files?

No. Preview creates a new merged PDF and saves it separately. Your original PDFs stay exactly as they were. You can delete the merged file or the originals without affecting the other.

What if one of my PDFs is password-protected?

Preview will ask you to enter the password when you try to open it. Once you enter the password, Preview treats it like any other PDF and you can merge it normally. The merged file will not be password-protected unless you add protection yourself after merging.

Can I merge PDFs from different sources — like one from email and one from my computer?

Yes. Preview does not care where the PDFs came from. You can merge a PDF you downloaded, one you received in email, one you scanned yourself, and one you created in another app. Just open them all in Preview and export.

How large can the merged PDF be?

Preview can handle merged files up to several gigabytes, but your Mac needs enough free disk space to save the result. If you are merging very large PDFs and your Mac is running slowly, close other apps and try again. If it still does not work, your Mac may not have enough memory — in that case, merge fewer PDFs at once.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.