Mar 09

Depending on what program you used to create a PDF, the file size of your PDF file can be quite large. If you combine two or three PDF files together using preview, you can also end up with a bloated PDF file.  The best way to reduce PDF file size is with Acrobat professional, which can do all sorts of magic on PDF files. Sadly we can’t all afford Acrobat Professional, so here is a free way to make a PDF file smaller.

Firstly, open the PDF file in ColorSync utility. The ColorSync utility is found in the utility folder of the applications folder of your computer. If you don’t know how to find that, simply right click (or option click if you have a one button mouse) on the PDF file, and select from the menu open with,  ColorSync utility.


This will open your PDF file in colour sync utility. Go down to the bottom of the window to the drop-down menu on the left that says ‘Filters’  and select ‘reduce File Size’.  Then click the button in the bottom right  of the window that says ‘Apply’.


Select the filter that says reduce file size


This will go through and re-compress the images in your PDF to make the file size smaller.

The images will not be quite as sharp, but the field will be much smaller.

Don’t forget to save the file after you’re finished.

You may want to use ‘save as’  instead of ‘save’ so that you still keep the original (higher quality) version of your PDF file.




If you want to be able to change the quality of the file that is saved, check out this great article from macworld:

59 Responses to “How to reduce the size of a pdf document in OS X”

  1. C. Hawkins says:

    Easy Fix! Reduced my 90.1 MB PDF to 800 KB. Thanks a bunch!

  2. Matt says:

    Also have a look at – it’s a great little tool that does good compression but maintains the quality.

    • Eyrekr says:

      This website works for me!My file size reduced from 5.6MB to 1.1MB. However, I don’t know the reason why my file size doesn’t change after using Colorsync… Thanks anyway!! :)

  3. Biraj Naidoo says:

    Thanks for the great tip! Much appreciated.

  4. Mary Ann says:

    This information helped me immensely. Every file comes in as number 1. Is there a way to change that?

  5. Carol Bartles says:

    This recommendation is incredible. Thank you, Thank you so much.

  6. Lama says:

    Great tip! this worked reduced my file from 7.8M to 1.1MB! So helpful

  7. Diane says:

    Thanks SO much!!!

  8. Jessica says:

    AMAZING! They’re a bit grainy but it worked. I needed to upload copies of my transcripts for a job posting, but the PDFs were too big. I’m a wiz with the fancier versions of Adobe you see in offices, but this was so helpful!

  9. Brook says:

    Awesome! My printer wouldn’t print my 4.5 mb pdf file but I was able to reduce it to 200 kb and it printed just fine! Thanks a lot.

  10. may says:

    Amazing! Thanks a bunch!
    Just a note that if you had anything highlighted on the PDF through Preview, they disappear after the file reduction!!

  11. anne says:

    Worked for me, thanks so much!!

  12. SK says:

    I needed to compress my file for a resume upload and this took my pdf from 3.3 MB to 410 KB. Thank you, thank you!

  13. Rod says:

    So how do you remove pages from a PDF? Sometimes I get manuals that are for several different versions of the same product. More often, I get manuals half of which are in Spanish, which I cannot read, and sometimes several different languages, only 2 of which I can read.

    I don’t want to waste the disk space and the extra time it takes to open a PDF that is at least twice as large as it needs to be.

  14. Fabio Buhr says:

    Thank you so much for this, very helpful and uses ready to use resources!

  15. Edgard Ade says:

    Original file: 315KB
    ‘Reduced’ file through ColorSync: 324KB.

    Not working for me on Yosemite.

  16. Toby Adobe says:

    This seems to work well.

    But I don’t understand why Acrobat bloats the files in the first place. I converted a 12.1 MB file to pdf format on a PC using Acrobat and got a 227 KB file. I did the same thing on a Mac using the trial version of Acrobat XI and got a 61 MB file. Using your method resulted in a 337 KB file.

    Needless to say, I’m not going to purchase Acrobat XI.


    • Wayne says:

      The larger the file the better the quality of the pictures. If you are going to print the file, which is what Acrobat was originally for, then the files should be big to get the best quality. So making a file smaller is for when you want someone else to view the file, but not print it. Adobe Acrobat Professional does have the ability to make the file smaller – just select ‘Save As… Reduced Size PDF’ from the menu.

      • Toby Adobe says:

        The Adobe folks got back to me. I originally created the pdf using “Create pdf from File” from the “File” menu in Acrobat, which increased the file size by a factor of 5 to 61 MB. They suggested you’re supposed to “Save as Adobe pdf” from the “Print” options within MS Word (“File” pull down menu). Doing so produced a 209 KB pdf file.

        I may yet purchase Acrobat for some of its other features though because of your method it’s not quite so essential. Thanks for your help.

  17. Pat says:

    So funny … you buy a Mac for thousands of Dollars or Euros … it makes PDFs of ridiculous size. All people not singing the praise of an OS that creates PDFs as a built-in feature notice that there is a flaw. You then find a work-around to reduce those bloated PDFs to acceptable size and all Mac users think this is a gift from heaven.

    WAKE UP, you Mac folks!

    How about you find a way to make your silly Mac OS produce reasonably sized PDFs in the first place? THAT would be the fix for the actual problem.

    Sorry, really no offense intended. I really appreciate this hint. Just would like people to realise that fixing the root cause would be even more helpful.

    • Wayne says:

      Pat, it’s important to be able to have large size pdf files as when pdf files are used for printing they need to be large. When you make them smaller it compresses the images so you do lose some quality. So yes, it’s handy to have them small, but it’s not desirable to have all pdfs small.

  18. MatW says:

    Thanks a LOT !! That works !

  19. neil cliff says:

    It’s really far simpler than that!

    Select document to be compressed. Then
    File-Export-Quartz Filter-(scroll down)-Reduce File Size-Save

    Make sure you title “Reduced File” and select where you want to save it to. Typically a 10:1 compression.

  20. mark says:

    one of the simplest , most straightforward and effective computer tips I’ve found.

    Thanks very much

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