How to Reduce PDF File Size on Mac: 3 Easy Ways

Creating and editing PDFs is easy. However, the same isn’t true about storing or sharing them online. Thankfully, you can save yourself some trouble by reducing the file size of your PDFs.

But how do you do that? And is there a way to do it without compromising on quality? Read on to learn the different ways to reduce PDF file size on a Mac.

Reduce the PDF File Size on a Mac Using Preview or ColorSync Utility

Using the Preview or the ColorSync Utility app is the easiest way to reduce the PDF size on a Mac. Both apps come pre-installed with macOS and have a built-in filter to help you resize files. You can use either to reduce a PDF’s size, as shown below.

Reduce a PDF’s File Size Using Preview

1. Open Finder and find the PDF you want to resize.
2. Double-click the file, and it should open in Preview. If you’ve changed the default program to open PDFs, Control-click on the file and select Open With > Preview to open it in Preview.
3. Once the file opens, click on File in the menu bar and select Export.
   
4. In the pop-up window, click the drop-down button next to Quartz Filter and select Reduce File Size.
   
5. Hit Save to save the resized PDF file on your Mac.
   

Reduce PDF File Size Mac Using ColorSync Utility

1. Find the PDF you want to resize in Finder.
2. Control-click the PDF and select Open With > ColorSync Utility.
3. Click File in the menu bar and select Export.
   
4. Hit the drop-down button beside Quartz Filter and select the Reduce File Size filter.
   
5. Give the file a name.
6. Click Save to save the resized PDF.
   

When you resize a PDF using Preview or ColorSync Utility, it also impacts the file quality. Sometimes, if the PDF wasn’t high-quality already, resizing it can make it blurry—to the point where the text and images become illegible.

Reduce PDF Size on a Mac Without Losing Quality

Preview and ColorSync Utility use the Reduce File Size filter to reduce the file size of a PDF by default. This filter is set to use low conversion settings for size reduction, which results in quality loss.

However, it’s possible to reduce the size of a PDF with Preview and ColorSync without losing quality. It requires creating a new filter and using that for resizing. Here’s how you do that:

1. Open the ColorSync Utility app.
2. Click on File in the menu bar and select New Window.
3. Go to the Filters tab.
4. Click the document icon next to the Reduce File Size filter to create its copy.
   
5. Double-click on the filter and give it a name.
   
6. Hit the arrow button to the left of the Reduce File Size copy filter under Custom Filters to expand it.
   
7. Now, expand Image Sampling.
   
8. Here, make sure the Quality parameter is set to High and change the Set Resolution value to 300.
   
9. Next, expand Image Compression. Then, click the drop-down button next to Mode and select Uncompressed.
   

Now that you’ve created the new filter, the rest of the process is easy. Depending on your preference, open the PDF you want to resize in Preview or ColorSync Utility. Then, follow the steps in the section above (based on the app you’re using) and apply the filter you just created. Save the file, and you’ll now have a resized version of the PDF without any significant loss of quality.

Reduce the PDF Size on a Mac Using Adobe Acrobat

Sometimes, a small file size is your top priority. In such scenarios, you can use online tools. Adobe Acrobat’s PDF Compress tool is popular tool for resizing PDFs. It’s easy to use and accessible on any device,. You can reduce a PDF’s size with it like this:

1. Visit Adobe’s PDF Compress tool in a web browser.
2. Click on Select a File, and when it opens Finder, select and open the PDF you want to resize. Alternatively, you can drag and drop the PDF directly onto the website.
   
3. Once the PDF is uploaded, select a compression level between Low, Medium, and High, based on your preference.
   
4. Click the Compress button to begin compressing the PDF.
5. After the PDF is compressed, click Download to download the compressed PDF file to your Mac. You may need to sign in to download the PDF.
   

Choose the Right Method for Best Results

You can use any of the methods above to resize PDF documents on your Mac. However, since they all return PDFs with different sizes and quality, it’s crucial to choose the right method for the best results.

In my experience, Adobe’s online PDF compressor manages to reduce the size of a PDF substantially but with a significant drop in quality. On the other hand, the Preview and ColorSync Utility methods—with the default filter—do a better job, albeit with a larger file size. As such, both methods are fine for resizing text-based PDFs; you should avoid them when you want to reduce the file size of graphics-rich PDFs.

For such PDFs, creating and using the custom filter in ColorSync Utility or Preview is the best approach. Not only does it reduce the PDF file size significantly, but it also ensures the quality of images isn’t compromised.