How to Compress PDF File Size on Mac, Windows & Mobile

Tips • Nov. 22, 2023

compress pdf guide

We all have been using PDFs for several reasons, and while they are convenient to work on, sometimes the large PDF can cause issues with file transfer and corruption. Also, you’re offered limited options for batch processing or automating repetitive tasks.

In such a scenario, arguably, the best way to address issues caused by large PDFs is by compressing them. While it might sound complicated, with the enhancement of PDF tools and software, it can be done in a few steps.

If you’re working on downsizing PDF without losing quality for the first time, it can be tricky, and we are going to ease it for you by offering approaches curated according to the platform with detailed steps for each.

RELATED: How to Edit Scanned PDFs (A Full Guide)

Key Takeaways

  • Compressing PDFs is crucial for easier transfer and prevention of corruption.
  • Windows users can use Word or open-source software like PDFShrinker.
  • Adobe Acrobat Pro DC is a user-friendly paid option for Windows and Mac.
  • Mac users can use Preview or opt for free/paid third-party software like Lightweight PDF or PDF Expert.
  • Online tools like Adobe PDF Compressor and Small PDF offer platform-independent solutions.
  • Mobile users can use the iLovePDF app for cross-platform PDF compression.
  • Caution is advised during PDF compression, and backups are recommended.

Compress a PDF File on Windows

Using Word (Built-In Approach)

Unfortunately, Windows doesn’t feature a tool that can help you compress PDF into smaller size. However, considering most Windows users arguably use Microsoft 365 or Office, it can be used to make a PDF smaller.

Note: While the below steps are a great way to shrink the size of PDF, this approach is more like converting a Word to a PDF file. We have suggested this as a built-in alternative for those who don’t want to install any application.

  1. Start by opening your Word document, navigate to the File menu at the top left corner of your screen, and click on it.
  2. Now, from the list of options, click on Export and then Create PDF/XPS Document.
  3. Next, a dialog box will appear. Here, select Minimum Size (publishing online).
  4. Now, click on Publish. By doing this, you’re finalizing the process, and your Word document will be converted into a compressed PDF file.

RELATED: 6 Ways to Convert PDF to Word on Mac (Free & Paid)

Using PDFShrinker (Open-Source Software)

Most developers arguably prefer Windows and Linux for developing projects. Hence, you might notice open-source software being available for various purposes. If you’re looking specifically for PDF compression with no restrictions, check out the below steps:

  1. Start by opening your preferred web browser and downloading PDFShrinker from its GitHub repository.
  2. After downloading, proceed to install GPL Ghost Script, as it is necessary for the PDFShrinkerto work.
  3. Once the installation is complete, launch PDFShrinker. Next, you can either drag and drop your PDF file into the application or use the or Open them here button to load your PDF.
  1. After loading your PDF into PDFShrinker, wait for the software to process it. Once the compression is complete, you’ll find the smaller-sized PDF in the same location as the original file.

Using Adobe Acrobat Pro DC (Paid Third-Party Software)

While open-source tools are arguably the best, many won’t consider them for their lack of intuitive interface and complexity while installing and setting them up. If you feel the same with PDFShrinker, consider checking out the steps below for compressing PDF using the prominent Adobe Acrobat Pro DC.

  1. Start by opening Adobe Acrobat Pro DC on your computer. Once it is loaded, you’re greeted with the home screen. Now, navigate to the Tools section and click on it.
  2. Begin with locating the Optimize PDF tool, and under the Protect & Standardize section, you will find the option – Optimize PDF. Now, select Add from the drop-down menu of the icon and select Open to open the dialog box.
  1. Doing so allows you to navigate to and select the PDF file you wish to compress. Once you’ve found your file, open it in Acrobat.
  2. Next, look for the Advanced Optimization button located in the toolbar just above the preview of your PDF, and clicking this button initiates the compression process.
  1. Now, refer to the below image and make changes accordingly. While you can make changes as you wish, it’s best to select Retain Existingto ensure your PDF remains compatible with the latest version of Acrobat.

Compress a PDF File on a Mac

Using Preview (Built-In Approach)

Unlike Windows, MacOS offers a built-in tool to manually reduce the size of a PDF through Preview, and it is exceptionally easy and reliable. If you’re a MacOS and want to compress PDF into smaller size, here are the steps below:

  1. Start by navigating to the PDF on Finder and right-click on it to reveal options. Now, from the options, click on Open With and then Preview (default).
  2. After the PDF file is loaded on Preview, navigate to File and click on it to reveal options. From the available options, click on Export.
  1. Doing this opens a new window, and from the available options, navigate to Quartz Filter. Now set the drop-down to Reduce File Size and click on Saveto compress the PDF.

Using Lightweight PDF (Free Third-Party Software)

Unfortunately, we couldn’t find any open-source software to compress PDFs on Mac. For this, we have tried several free third-party software and here are steps on how to use PDF Size reducer Lightweight PDF:

  1. Start by opening the Mac App Store and search for Lightweight PDF. If you can’t find it, navigate to Lightweight PDF on the browser.
  1. After the software is installed, drag and drop a PDF from Finder, and the PDF compression starts right away.

Note: We have selected Lightweight PDF for ease of use, but if you’ve any other free software up on your mind, ensure you check the reviews and ratings before downloading.

Using PDF Expert (Paid Third-Party Software)

If you’ve already tried compressing PDFs with Preview and found its interface or functionality somewhat complex, you might have considered Lightweight PDF as a simpler alternative.

While Lightweight PDF is indeed user-friendly and straightforward, it’s crucial to remember that its simplicity may limit your flexibility in compression options. In such cases, turning to more comprehensive Mac PDF editors is advisable.

However, considering the higher costs of Adobe Suite on Mac, PDF Expert emerges as a cost-effective alternative, and below are the steps to compress PDFs using PDF Expert efficiently:

Note: Before checking out PDF Expert, it’s worth noting that if you’re using Adobe Acrobat Pro DC on Windows, the same steps apply to its Mac version for compressing PDFs.

  1. Start by downloading and opening PDF Expert. Next, please navigate to the File menu at the top left of your screen and click on it.
  2. Now, from the available options, select Reduce File Size and choose the desired quality for the compressed file. The best part of PDF Expert is it shows the approximate reduced size, assisting you in the process.
  1. Now, click Saveto compress your PDF. You can opt to save it as a new file or share it immediately.

Compress a PDF File Online

Considering most people arguably use Windows and MacOS, those on other platforms might not have access to these tools. However, irrespective of the platform you’re using, all have web browsers in common.

Hence, we have included online PDF editor tools, and after checking arguably the prominent ones, here are our best picks, along with steps for each on how to compress a PDF:

Using Adobe PDF Compressor

  1. Start by visiting the Adobe PDF Compressor on any browser of your choice on any platform.
  2. Then, upload your PDF file by dragging it into the designated area or by browsing your files.
  1. Doing so initiates the compression process, where Adobe’s advanced algorithms work to reduce the file size while maintaining quality.
  2. Once the process is complete, you’ll see a preview of the compressed file.
  3. Now, you can download the compressed PDF to your device or save it to cloud storage services like Dropbox or Google Drive.

Using Small PDF – PDF Compressor

  1. Begin with navigating to the Small PDF – Compressor tool on any browser of your choice on any platform.
  2. Next, choose the PDF file you wish to compress either by dragging it into the window or selecting it from your device.
  1. After uploading, Small PDF automatically starts compressing the file, balancing quality and file size.
  2. Then, you’ll see the option to preview and download the compressed PDF.
  3. Additionally, Small PDF offers the choice to adjust the compression level further if needed, making it ideal if you want to compress PDF to 50KB, 100KB, 150KB, 200KB sizes.

Compress a PDF File on Mobile Devices (Android and iOS)

Like Windows and iOS, you have multiple choices for PDF Compressors on Android and iOS on the respective application stores.

While it’s true that most of these apps deliver on their promises without offering anything particularly new, we’ve searched for an app that stands out in terms of cross-platform compatibility and has led us to iLovePDF.

Note: Even though the iLovePDF app has the same interface on both Android and iOS, there might be minor changes. Hence, consider the steps below as generic and use them for both platforms.

  1. Start by downloading iLovePDF on Android and iOS from their respective app stores.
  2. After the app is loaded, navigate to Tools present at the bottom and tap on it.
  3. Doing this, you’re displayed with multiple tools from which you tap on Compress PDF.
  4. Now select the PDF, choose the compression that suits your requirement, and tap on the Compress PDF button, and you’re done.

Wrapping Up

We hope that the tools and software listed according to the platform with detailed steps have got you completely covered and you were able to compress a PDF with ease.

While none of the approaches affect the original PDF file, and a separate compressed PDF is created, make a backup if you’re worried about the original file and don’t want to make any modifications to it.


How do I check my PDF file size?

There are multiple ways to check the PDF file size. However, the easiest would be navigating to the PDF on File Explorer and placing the cursor on it to reveal the file size.

How do I compress a PDF without losing quality?

While all the above approaches focus on compressing PDF without losing quality, it is inevitable. However, you make the quality loss insignificant and negligible by adding fewer images to the PDF.

What’s the difference between compression and flattening?

PDF compression reduces file size by compressing data and maintaining the document’s structure. Flattening, on the other hand, merges layers into a single image, potentially reducing editing capabilities.