How to merge two pdf files in OSX

Thanks so much. Your explanation is brilliant. Easy to follow. Better than apple support itself. :)

OS X comes with a free application called ‘Preview’ that will open automatically whenever you click on a pdf file. Preview can edit and merge pdf files but the official Apple instructions are not quite right. Here’s how to do it depending on which version of OS X that you have.

You can merge PDF files using the built in ‘Preview’ application that comes for free with OSX, you don’t need 3rd party paid software.

The basic concept for merging 2 pdf files is the same for whatever version of OS X you have. You open the first file, view the page thumbnails, then drag the second file into the first file and save the new file.  Exactly how this works varies depending on which version of OS X that you have. Apple have changed the details a few times. Sometimes there’s a green plus sign to indicate the merge. Sometimes there’s a grey border. If you don’t get it right the 2 files will not merge.  You need to read the directions for the exact OS version that you have. (To find out which version of OS X you have just go to the Apple Menu and click ‘about this mac.’)

Please click on the version of OS X that you have to find out how to merge a pdf file:

How to merge PDF files in High Sierra (10.13)  (2018)

How to merge PDF files in El Capitan (10.11) (2015)

How to merge PDF files in Yosemite (10.10) (2014)

How to merge PDF files in Mavericks 10.9 (2013)

How to merge PDF files in Mountain Lion 10.8 (2012)

For all versions of OS X prior to Mountain Lion (10.7 and earlier)  just follow the instructions below.

Here’s how to  join two or more pdf files together using Preview in OS X 10.7 and earlier:

1 Open the pdf file in preview.

2. Open the thumbnail view (Shift-⌘-D)

3. Drag a second pdf ON TOP OF an existing page  thumbnail.

When you drag in step 3 it must drag to on top of the thumbnail, as in over it, not above it.

This is a bit hard to explain, the best way to grasp the concept is to look at the pictures below. Can you notice that the thumbnail on the right has an extra grey border compared to the thumbnail on the left. The grey border indicates that the files are merging.

WRONG WAY: If you drag the new pdf file underneath the existing pdf they are not merged.
RIGHT WAY: Drag the new pdf file overlapping an the existing page and they will merge into one – creating one pdf document out of the two. (Notice the extra grey border compared to the left photo.)





SUMMARY: To combine two separate PDF files into one document you need to drag the new pdf ON TOP OF an existing  thumbnail until the grey border appears – then it will merge the two pdfs together.  (You can then save the new merged pdf.) 

If you drag it into the sidebar but not on top of an existing page the new file will be added as an external link – not merged into the original pdf document.

Published Date:Last Updated: Dec 2017.

Read on for how to do it step by step.


585 responses to “How to merge two pdf files in OSX”

  1. Rakesh

    Thanks so much, this was really useful

  2. Catia

    I followed these instructions, but ….!!!
    Now in my Preview, in the thumbnails’area, i see my ​​3 pdf pages, that I want to merge, but then, there is no way to merge them really: if I save this file, only the first page is saved, if I try to print it, only the first page is printed.
    How it works??? Please…I feel so stupid…

    1. Catia

      I tried again!! We must put the new pdf NOT ON THE TOP (as these instructions say) but just OVER the existing page! OK, so it works

      1. Yes ‘over’ as in put it right in the middle of the thumbnail, as if you were putting one piece of paper on top of another piece of paper in a pile of paper… not ‘above’ it as in ‘up’ the screen. English is a bit ambiguous at times!

  3. Joseph

    Awesome article. Thanks! The print-to-PDF solution was perfect and simple.

  4. Bill

    Coolio. Works a treat and saved me loads of time. Cheers.

  5. matt


  6. Janos

    Very good explanation, It helped! thanks

  7. Katrina Currier

    Thanks for these helpful tips! Can you explain how to undo these actions? I have merged too many pages and now want to delete a few of the pages I dragged in, without deleting the whole merged file. Is this possible? Thanks!

    1. In thumbnails click on the page and press delete. It’s that easy.

  8. Mary

    Great!! Thanks a lot, the process is way to fast and easy :)

  9. Rubi86

    Thank you! it worked :)

  10. Ian

    This is great and worked perfectly. I became an Apple convert some years ago, in a computing context it was the best thing I did.

  11. Ade

    thank you so much. this really helpful !! :)

  12. jeanh


  13. EFalk

    Such a small detail, but figuring out the right way such that you can actually save the combined document was SO helpful!

  14. Lisa

    At midnight and after hours of frustration, this was a God-send! Thank you so much.

  15. SK

    Thank you SO much! I kept putting the thumbnails after the original (like on a PC) and it obviously didn’t work. I’m so thrilled and grateful!

  16. Otto the Automator

    The ability to combine (merge) multiple PDF files into one file in the Finder is built-into OS X, you just have to turn it on:


    1. Looks great. Although that’s a very complicated way to do a very simple task that can be done much more simply in Preview. But, it might be good if you have a lot of pdf files to merge or you do this task on a regular basis. Thanks for the link.

  17. Richard

    This is not working for me, no double border appears, files don’t merge, remain as 2 documents

    1. What version of OSX do you have? Are they both pdf files?

  18. TYBAN

    This article is worthless, doesnt work

  19. Keith

    I usually consider myself savvy when i read these tips, but I’ve spent 90 minutes trying to make Lion do what this article says it will do with absolutely no luck.

    The sidebar method doesn’t work either. When I click on “view” and scroll down to “sidebar”, I’m offered two dead grey choices, neither of which are clickable (“collapse all” or “expand all”). No sidebar appears anywhere.


    1. Keith it’s different in OSX Mavericks. In Mavericks it’s ‘View’ ‘Thumbnail’ not ‘View ‘Sidebar’. There are also other differences. I have a separate article for Mavericks here:

  20. Mariana

    Thank u very much, saved my life, I was going crazyyyyy

  21. Ken

    Thanks for taking the time to put these steps on the web! I’m not sure why some are having problems. It worked perfectly for me. I really appreciate the detailed instructions.

  22. Park

    Thanks! . . . Works easily.

  23. Danny Coyle

    I used this and it worked except it changed the landscape pages to portrait and messed them up, help?

  24. Hannah

    I can easily follow the steps and drag one file ON TOP of the other and I see the double boarder. But once I release the second file on top of the first, nothing happens…? I’m lost what to do next! I tried to Save As and reopen, but its only the 1st file. Any suggestions?

    1. Strange. Can you try it with 2 different pdf files and see if it works. Maybe one of the files you are using is locked.

  25. Lanelane

    Worked for me. Thanks

  26. Brilliant.
    So simple, so obvious.
    So simple and obvious that it needed to be pointed out!

  27. Jakob

    This was soooo helpful. Can’t thank you enough. After spending hours trying to find another program, sometime it’s the simplest solutions. Many thanks!

  28. John Satan

    Excellent tip! Took some doing, though…in my version of 10.6.8 I had to ‘select all’ pages in the sidebar and then click ‘Print Selected Pages’ in order for all to be merged into one file. Thank you.

  29. THANK YOU! After many web searches for answers and tons of waisted time trying to combine PDFs – finally you have provided a real solution that WORKS.

  30. very helpful, thanks

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