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How to Reduce PDF File Size on a Mac

December 28, 2021
Author
Inkit Team

PDF files are usually packed with images and graphics, making their file size quite heavy. They usually end up taking a lot of space on the disk, and time in uploading and downloading. However, there are ways in which you can compress and optimize them without compromising on quality. In this post, we’ve shared the top ways in which you can reduce PDF file size on a Mac.

We’ve covered the best options, be it online or offline. Also. If you are only looking to compress a few PDFs, then we’ve discussed how you can do it by utilizing macOS’ built-in functions. Let’s dive in!

How to Reduce PDF Size on a Mac Using Adobe Acrobat?

You can reduce the size of a PDF file without losing its quality through Adobe Acrobat. You can do it both, online and offline. However, you need to have the paid version, i.e., Adobe Acrobat Pro, to use the offline feature. 

How to Reduce PDF File Size on a Mac Using Online Adobe Acrobat Tool?

Step 1: Open the Adobe compress PDF Webpage

If you want to use Adobe’s online tool for compressing PDFs, then click on this link. It’s one of the safest options to optimize PDFs online. The following page will open.

adobe compress pdf webpage

Step 2: Open Your PDF File

Click on ‘Select a File’. The ‘Open’ dialogue box will open. Navigate to the file that you want to compress and click on ‘Open’.

compress pdf file upload

Step 3: Choose Compression Level

Adobe’s online compression tool will ask you to choose a compression level from high, medium, and low. The medium option is chosen by default, but you can switch it to high or low. The high compression option has the highest reduction capability, but its quality will be the lowest. We’d suggest going with low compression when you have a lot of images in your PDF file.

compression level for pdf upload

Step 3: Compress and Save the New PDF

After choosing your desired compression level, click on ‘Compress’, and Adobe’s Compress PDF tool will start doing its magic.

compress pdf level choose


You’ll see a window as given below when the PDF optimization is done. Click on ‘Download’ to download the compressed PDF file.

download compressed pdf size

How to Reduce PDF File Size on a Mac Using Adobe Acrobat Pro?

Step 1: Open the Adobe Acrobat Optimise PDF Tool

The first step in optimizing a PDF file in Adobe Acrobat Pro without losing quality is to open its Optimise PDF tool. You can do this by accessing the Tools tab, which is at the top left corner of the window. Find the Optimise PDF tool, click on the drop-down, and select ‘Open’.

adobe optimize pdf tool
Image via Acrobat


Step 2: Select the File to Compress

On selecting ‘Open’, a dialogue box will open. Navigate to where you’ve saved your PDF file and click ‘Open’.

open pdf file to compress
Image via Acrobat

Step 3: Reduce File Size

Once the file is open, click on ‘Reduce File Size’, which is the first option above your open PDF.

reduce file size pdf
Image via Acrobat


A dialogue box titled ‘Reduce File Size’ will open. This option allows you to change the compatibility of your file. If you don’t want to make any changes, then keep the default setting of ‘Retain Existing’ and click on ‘Ok’.

reduce file size adobe
Image via Acrobat

Step 4: Rename and Save Your File

Now your file has been optimized, so it’s time to save it to retain the changes. Click on ‘File’ and then ‘Save As’ to save the file. A new window titled ‘Save As’ will open, navigate to the folder where you want to save your optimized file. You can either overwrite it or save it as a new file. Finally, click ‘Save’.


choosing file to reduce pdf size
Image via Acrobat

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How to Reduce PDF File Size on a Mac Using macOS Tools?

If you don’t want to pay extra for software to reduce your PDF files’ sizes or don’t want to upload them onto sketchy webpages, then you can do it through the Preview function provided in macOS.

Here’s how:

How to Reduce PDF File Size on a Mac Using Preview?

Step 1: Add Filter Options for the Preview Export

Preview only provides you with the option of reducing file size, which is often, by default, set to low quality, leading to a reduction in the PDF file’s quality. However, you can tackle this by adding more quality options in it by using ColorSync Utility.

Start by opening ‘Applications’ and then ‘Utilities’. Click on ColorSync Utility. Head over to the Filters tab and select the ‘Reduce File Size’ option from the list. 

Click on the horizontal arrows on the left to expand the menu. Here, you’ll see that the default size is set to a maximum of 512 pixels, which isn’t sufficient, and thus, leads to poor quality PDFs when used for reducing the file size in Preview.

reduce file size copy mac
Image via macsales


Now, click on the right arrow to get a new dropdown list. Here, select ‘Duplicate Filter’. You’ll notice that a new filter named ‘Reduce File Size Copy’ has appeared at the bottom of the list.

The target here is to create three varying custom resolution and quality settings:

  • Reduce File Size (100 dpi, low quality)
  • Reduce File Size (100 dpi, high quality)
  • Reduce File Size (150 dpi, high quality)

Therefore, create three filters. Click on the arrow at the left of the filter to open it and access its settings. Double click on the name to change it. Choose the quality option as per the name of the filter. 

reduce pdf file size high
Image via macsales


The custom filters have been created and will appear in the Quartz Filter’s dropdown list, allowing you to maintain the quality of PDF despite reducing its size. 

Step 2: Open the PDF File in Preview

Preview is the default PDF viewer in the macOS, so whenever you open any PDF file, it opens in it. Navigate to the folder where you have placed your file, and double click it to open it in Preview. 

Step 3: Reduce the PDF Size in Preview

Click on ‘File’ and select ‘Export’. Next, click on the dropdown next to Quartz Filter. Here, you’ll see the three filters that you had created earlier. Choose the 150 dpi one, if you have images in your PDF file. The other options will work for text files.

Image via macsales


Save the optimized file by hitting ‘Save’. 

How to Reduce PDF File Size on a Mac Online?

There are numerous tools available online that offer the service of reducing PDF files sizes, but the issue is, you can’t trust just anyone with your precious documents. However, a few options are at the top of the game and ensure that your documents stay safe while being compressed. Among these online PDF compressors, our pick is Small PDF. Here’s how it helps you in reducing the sizes of your PDF files:

Step 1: Open Small PDF

Click this link to open the Small PDF’s online PDF compressor directly. This is how the webpage looks:

small pdf upload pdf compress

Step 2: Open Your PDF File

You have two options to upload your files to the Small PDF’s Compress PDF tool, either drop it onto the webpage or click on ‘Choose Files’. 

On clicking onto ‘Choose Files’, an ‘Open’ dialogue box will open. Navigate to the file that you want to upload and click on ‘Open’.

upload pdf files in smallpdf

Step 3: Choose Compression Level

The tool will ask you to choose either a basic or strong compression level. The strong compression level requires a paid membership, but you don’t necessarily need it. Basic compression will provide you with medium compression and high quality, which is workable in most cases.

basic strong pdf compression


Step 4: Optimise and Save PDF 

After choosing compression level, click on ‘Choose option’. The Small PDF Compress tool will start the compression process. After the PDF is optimized, click on ‘Download’ to download the new compressed PDF file. 

How to Reduce PDF File Size on a Mac Using Cisdem?

If you require PDF file size reduction on regular basis, then you’re better off with having software than doing it online. Our pick is Cisdem PDF Compressor because it is easy to use and offers a free trial, so you know what you’re getting before investing. Here’s how you can use Cisdem to reduce PDF file size on a Mac.

Step 1: Download and Install Cisdem 

Click on this link to directly reach the page from where you can download the free trial of Cisdem. 

Step 2: Drag and Drop Files

After downloading and installing the Cisdem PDF Compressor, open it, and drag and drop the files that you want to optimize. 

Step 3: Choose a Compression Option

Next, choose from four available compression options. These include:

  • Small file size (low quality)
  • Medium file size (medium quality)
  • Large file size (high quality)
  • Custom

Step 4: Compress the PDFs

After choosing a compression mode, click on ‘Compress’ to start optimizing your PDF file.

Hope this guide on reducing your PDF file size on Mac helped!

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