How to reduce PDF file size using Acrobat 9

By Adobe Systems – July 20, 2009


In this tutorial, learn how to reduce a PDF file size (sometimes called optimize PDF or compress PDF) without having to regenerate the PDF file, regardless of the preset used to create a file. The size of a PDF file can vary tremendously depending on the Adobe PDF settings used to create the file. For example, files created using the High Quality Print preset will be larger than files created using the Standard or Smallest File Size presets. Regardless of the preset used to create a file, you can often reduce the file size without having to regenerate the PDF file.

In this section, you'll use the Reduce File Size command to dramatically reduce or compress the size of a PDF file.

  1. In Acrobat, open a PDF file.
  2. Choose Document > Reduce File Size.
  3. Select Acrobat 8.0 And Later for file compatibility, and click OK.
  4. When you choose the compatibility level, be aware that the newer the version of Acrobat that you choose, the smaller the file. If you choose compatibility with Acrobat 9, however, you should be sure that your intended audience does indeed have version 9 installed.

  5. Name the modified file. Click Save to complete the process.
  6. It is always a good idea to save a file using a different name so that you don't overwrite an unmodified file.

    Acrobat automatically optimizes your PDF file, a process that may take a minute or two. Any anomalies are displayed in the Conversion Warnings window. If necessary, click OK to close the window.

  7. Minimize the Acrobat window. View the size of the reduced file. The file size is smaller.
  8. You can repeat steps 1-5 using different compatibility settings to see how they affect file size. note that some settings might actually increase the file size.

    PDF Optimizer offers more opportunities to control quality trade-offs.

  9. Choose File > Close to close your file.
  10. Excerpted from Adobe Acrobat 9 Classroom in a Book. Copyright © 2009 Adobe Systems Incorporated. Used with permission of Pearson Education and Adobe Press.

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Acrobat 9

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Lori Kassuba

4 days ago


You’ll need either Acrobat Std or Pro. to use the Reduce File Size feature.



6 days ago

how to reduce size of pdf file..


12, 2013-10-08 08, 2013

I have found that I can shrink the file size just by running the file through OCR recognition.  I just shrank a 12M file down to 5M.

Document > OCR Text Recognition

Abobakr Sultan

4, 2013-01-24 24, 2013

I followed those steps but it the file size (10.0MB) remained the same?

Hi Abobakr,

Some PDF files may not be able to be reduced in the file size. However, if you have the Pro. version of Acrobat you can try using the PDF Optimizer:


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