How to compress a PDF file on Mac

Would you like to reduce the size of a PDF file before emailing it or publishing it on your website but you don’t want to install on your Mac, just for that, expensive professional solutions? Don’t worry, you don’t have to, or rather you don’t have to. Depending on your preferences and needs, you can in fact compress a PDF file with Mac both by using the “standard” tools available on your computer and by turning to third-party solutions, so to speak, but in any case at no cost and in able to give you excellent results. In all cases, however, you do not have to worry, it is a very simple operation to perform.

Contrary to appearances and beyond what you may think I assure you that compressing a PDF file with Mac is a real child’s play, whether you are more or less expert in computer science and new technologies does not do much difference. By carefully following my tips and my indications, concentrating for a few minutes on reading what is reported below and keeping calm you should be able without particular problems to “lighten” your files in no time.

Then? What are you still doing standing there? Take a few moments for yourself, lie comfortably and immediately start putting my suggestions into practice. I am sure that in the end you will be able to tell you more than satisfied with what you have learned and that even in case of need you will be ready and happy to recommend all your friends who are eager and in need of receiving similar information. What do you say, we bet?


As I told you, to compress a PDF file with Mac you are absolutely not obliged to turn to expensive solutions that promise “miraculous” results. Everything you need is already on your Apple-branded computer: Preview . This is the default macOS / OS X application that displays photos and PDF documents. Perhaps not everyone knows this, but it can also be used to minimize the weight of PDF documents. If you want to find out how, having the choice between various compression levels, read on below.

To understand how to compress a PDF file with Mac using the Preview application, all you have to do is open the document to be “lightened” (by double clicking on it) and select the Export item  from the File menu located at the top to the left of the screen.

In the window that opens, select the PDF item from the Format drop-down menu , set the Reduce File Size option in the Quartz filter drop-down menu : and choose the folder in which to save the document in compressed version. Finally, click on the Save button and that’s it.

To check how much the weight of the PDF has decreased compared to the original document, check the properties of the two files by selecting them with the mouse and pressing the combination of keys cmd + i on your Mac keyboard. The weight is that indicated in the Dimensions field  ( Occupied disk space ). Of course, don’t expect miracles: compression is felt above all in documents rich in images, a PDF of a few pages consisting of text only will not be reduced by who knows how much.

Additional compression profiles

If after having compressed a PDF file with Mac following the instructions above you have found a too low quality in the latter, you can expand the Preview functions and make the PDF compression level more customizable by installing additional compression profiles .

How you do it? Nothing simpler! Connect to this website and click the Download ZIP button located on the right to download the compression profiles for Preview on your computer. When the download is complete, double-click on it to open the archive you just downloaded ( ) and copy all the files extracted from it to the Macintosh HD> Library> PDF Services folder . If you do not know how to get there, select the Computer item from the Go menu  located in the upper left part of the Desktop, double-click the icon of the hard disk on which macOS / OS X is installed and then go to the foldersLibrary> PDF Services .

After copying the compression profiles to your Mac, you can compress your PDFs with more precision by following the same procedure we saw above. Instead of Reduce file size , however, from the Quartz filter drop-down menu : you will have to choose one of the new options available: Reduce to 075 dpi average quality , Reduce to 075 dpi low quality , Reduce to 110 dpi average quality , etc.

The profile suitable for most cases, that is to say the one that is able to guarantee the best compromise between weight and quality of the output file, is Reduce to 150 dpi average quality but of course the lower the resolution of the document chosen and more ” lightweight ”will be the PDF obtained after compression.


Did Preview not meet your needs and did not use the above online services attract your attention in a particular way? So to compress a PDF file on Mac, you just have to rely on an ad hoc application but, don’t worry, it is not an “abstruse” tool: I’m talking to you about  ShrinkIt , a free and very easy application. to use … to the point that explaining how it works is almost superfluous!

In any case, to reduce the weight of your PDFs with ShrinkIt all you have to do is connect to the download page of the app and press the Download ShrinkIt button to download it to your computer. Once the download is complete, drag the software icon to your Mac’s Applications folder and double-click the ShrinkIt icon to start it right away.

Once the software window is displayed on the desktop, drag the PDF on which you intend to go to act in the ShrinkIt window and wait a few seconds for the program to process the document. ShrinkIt will then replace the original file with its compressed version and will create a safety copy (in a non-optimized version) in the same folder as the source file. Easier than that?

PDF Compressor

If you want, you can compress a PDF file with Mac also by operating from the browser, using some special online services. There are several resources on the net of this type, personally I recommend  PDF Compressor. It is an online service at no cost and very simple to use which, as the name implies, allows you to compress the size of documents in PDF format directly from the Safari window or any other program to browse online, all without installing anything on the computer. It has no limits to tighten you in terms of maximum weight of documents on which to act and allows you to intervene on a maximum of 2nd file at a time.

To use it, connected to the service site, then click on the Upload file button and select the PDF files to be compressed on your computer. Alternatively, drag files directly into the browser window, in the area marked Drag your files here. .

Then wait for the upload to start and complete (the duration of the process depends on the weight of the file and the speed of the Internet connection in use). For each file you have uploaded you will be shown, in correspondence with its preview, the percentage of compression that has been applied.

To download the compressed PDF files, press the Download button that you find next to each preview or click the Download all button at the bottom. If you have selected multiple PDF files, a folder with all documents with reduced weight will be downloaded to your computer. Unless you’ve made any changes to the default settings of the web browser you’re using, you should find the compressed document in  your computer’s Downloads folder.


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