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. alan

    so unbelievably simple and useful.
    thanks so very much for posting this.

  2. Jacquie

    This post was so helpful and relieved so much frustration! Your instructions are very clear and easy to follow. Many thanks!!!

  3. kyra

    So very helpful!

  4. Steve

    The only save option under “file” on my mac-air is “save a version”. And this does not save the merged document shown on the “Preview” sidebar. So, how can I save the merged document?

    1. Jane

      Duplicate the pdf first, then you can save that version normally.

  5. Wendy

    Very helpful article! Saved me a lot of time! THANKS!

  6. Jen

    Thank you! All these years had no idea Preview had a PDF file merge feature. This was very helpful.

  7. Patricia

    Brilliant – I’ve managed to merge several PDF’s – but now I have a document that is way bigger than the combined actual size of the PDF’s!!! Aaargh – any help for this Mac beginner greatly appreciated! :)

  8. Petri

    Why didn’t I know this before!

    I’ve been using my ancient Acrobat 5 full version until today… It may have avantages in complex situations – like combining a hundred Word-generated PDFs – but we’ll see. Maybe I can even contemplate Mountain Lion now.

    Thank you!

  9. Diana

    Thank you so much! For many years mac-user and never knew! Amazingly easy!

  10. jayanth

    I have OSX 10.6.8. The preview I have is not showing the grey back ground and the double grey background. Now how do I merge the PDFs.
    Thank you

  11. Rogue


  12. Zannie

    Thanks for this- I’ve had a mac for years and have always wondered how to do this.

  13. Susan

    THANK YOU!!!!

  14. Hayley

    Thank you so much!! Xx

  15. Ashley

    Excellent explanation :) Thanks!

  16. Iris

    Thank you, big help!

  17. you just totally saved my life man. thanks!

  18. Andi

    Cool! Thanks.

  19. John

    Very helpful tip

  20. Laura

    This was so easy! Thank you for this tip!

  21. Vtgeo

    Great to find this help to merge several pages (scanned as single pages)/pdf files into one multipage pdf. After some online researching and your helpful directions, I ended up scanning from my HP all-in-one printer/scanner directly into Preview (I’m amazed at how much is hidden in PREVIEW & what it can do besides display files) then combined the single pages back into one PDF just like the stapled, hardcopy stack of 11 pages I started with. Ended up scanning the text at 150 dpi to try to keep the file size down. Good quality & readability. Also instead of emailing all the files, I started a new Google Drive folder to share the PDFs with family. I did also try scanning with Image Capture, another free program on my old MacBook Pro -OS X 10.6.8. It worked well with my scanner too.

  22. Angela

    In Preview, Edit –> Insert –> Page from File also worked for me.

  23. Jasper

    Thanks, this emphasize* worked it out!

    ON TOP OF an existing thumbnail

  24. Lisa Currier

    This information was very helpful and worked like a charm!
    Thank you!

  25. Karolina

    is it possible to merge more than 25 pages? Mine only allowed up to 25. I’m using Mountain Lion.

  26. Renata

    Thanks so much for this! Came in handy while sorting my portfolio.

  27. Cat

    Thanks, worked like a charm!

  28. Keith

    The instructions for merging pdf’s on Snow Leopard worked like a charm. THANKYOU.

  29. I didn’t know this trick, it works perfectly. Thanks!

  30. Linnea


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