PDF users may want to include images or graphics in their PDF documents to make them more illustrative and attractive to the eye. Larger PDF files, on the other hand, can slow down file transfers and collaborations. When faced with this problem, a PDF size optimizer can help. This post gets down to the best PDF file size reducers and elaborates on how to compress a PDF with ease.

How to Compress a PDF with Desktop PDF Tools

First and foremost, you should be aware of two factors:

  1. compression technology merely reduces the total file size and makes a PDF smaller by removing redundant data and downgrading image quality. Users don’t have to be concerned about file integrity because no information or data will be removed or eliminated from your documents;
  2. provided that the original file size is 10 MB and you want it compressed to or below 100 KB, such an action is almost impossible, and no PDF compressor can promise such an amazing compression result.

If you are looking for more advantages of reduced PDF files, this post offers more information.

Compress a PDF on Windows

Our editor has reviewed commonly-used PDF size reducers and hand-picked Windows-supported SwifDoo PDF and Foxit PDF for your reference if you're seeking sophisticated PDF compressors for Windows 11, 10, 8, or 7. Let's look at how to compress a PDF in order to make it smaller:

SwifDoo PDF

SwifDoo PDF is a Windows-based offline PDF compressor that is simple to use. SwifDoo PDF can better satisfy your demands for lowering PDF file size by providing three distinct degrees of picture quality.


Step 1: Go to the official website and download and install SwifDoo PDF;

Step 2: Click Open on the homepage to upload a PDF. Or, you can directly drag a PDF to the workstation;

Step 3: Select Compression from the Advanced tab;

Step 4: Choose the Image Quality and output destination folder. When everything is complete, click Start to compress this PDF. Shortly, you will reduce the PDF file size without losing file integrity.

Note:The file size after compression is an expected value and it is not the final file size. 

If in need of compressing multiple PDF documents into smaller ones, simply press “Add Files” to perform a batch-compression process. Notably, when the image quality of a PDF document must be maintained, it is strongly recommended that users check the box "HD" to ensure that the images are not affected by PDF compression.

                                                                      Free Download

Foxit PDF

In comparison to SwifDoo PDF, compressing a PDF file with Foxit PDF is more complicated than with SwifDoo PDF. Because Foxit PDF has extensive functions built into its operating panel, this is the case. Users may choose which sections to compress and how the images are shown once they've been compressed. Check out these tips for how to reduce PDF file size with Foxit PDF:


Step 1: Download and install Foxit PDF Editor on your PC;

Step 2: Launch the PDF program and click on the File ribbon;

Step 3: Place your cursor on the PDF Optimizer and click on Advanced Optimization;

Step 4: Change the settings if needed. When finished, click OK to compress a PDF.


Users can compress the items in the left column while adjusting the picture quality in "Color/Grayscale Images" or "Monochrome Images," as seen in the above image. In comparison to SwifDoo PDF, Foxit provides additional choices to reduce a PDF file.

Tips: "Reduce File Size" is a part of the "Advanced Optimization" functions. It utilizes the default settings of "Advanced Optimization".

LibreOffice Draw

Perhaps you are a stranger to this software however, LibreOffice Draw is an open-source PDF size reducer on Windows, Linux, and macOS. LibreOffice Draw is a free PDF compressor that can optimize the size of images in a document, resulting in a smaller PDF output. That's how you compress a PDF with LibreOffice. Users can change the image compression settings (lossless and lossy compression) and resolution (75, 150, 300, 600, and 1200 DPI) with its support.


Take a look at how to reduce the size of a PDF:

Step 1: Download and install LibreOffice Draw;

Step 2: Launch the open-source compressor and import a PDF to the workstation;

Step 3: Next, go to File and choose Export as PDF. Specify the newly created compression level and image resolution values;

Step 4: Hit the Export button to compress a PDF.

With this feature-rich free PDF compressor, users can significantly reduce PDF file size and make a PDF file smaller by optimizing the image resolution for free.

Note:LibreOffice Draw only reduces the size of PDF files containing images.

Compress a PDF on Mac

The default PDF compressor, Preview, makes it reasonably easy to minimize PDF file size on Mac. Multiple functionality, such as PDF file compression, conversion, and editing, are included in this built-in program. See how to compress a PDF on a Mac to make it smaller:

Step 1: Open a PDF that needs compression with Preview;

Step 2: Click File and choose Export (Tip: don’t mistakenly choose Export as PDF);

Step 3: Select Quarts Filter and click on Reduce File Size in the drop-down menu.

That’s all you need to know to reduce PDF file size on macOS without compromising quality. Though this freeware can act as a PDF size reducer, it can hardly batch-compress multiple PDFs at the same time. If you do need to batch compress PDFs, consider professional online tools in the forthcoming paragraphs.

How to Compress a PDF with Online Tools

It's reasonable that some users find it inconvenient to download and install a desktop PDF compressor. We do have a few excellent web-based PDF size reducers in this industry.


If you need to reduce the PDF file size online, PDFCompressor is a multi-language support Internet-based compressor you may put into good use. The website's design is simple and straightforward, with few complex interactive components. It's one of the things that makes PDF compressing on this platform so much easier:

Step 1: Type the URL in the search bar;

Step 2: Click PDF Compressor and upload the PDF to the workstation. When ready, the online tool will compress a PDF;

Step 3: After a while, choose Download to export the compressed PDF with smaller file size. Shortly, a reduced PDF will be automatically saved to your specified folder.


This online PDF compressor supports batch processing PDF documents. If needed, click “UPLOAD FILES” to continue adding more files to the workplace.


Smallpdf is a powerful PDF editor that lets you edit, convert, combine, divide, and compress PDF files. It's also an online PDF file size reduce that can compress PDF files to make them smaller. See how it makes compressing a PDF a breeze with only a few clicks:

Step 1: Choose Compress PDF;

Step 2: Upload a PDF document from a local folder, Google Drive, or Dropbox;

Step 3: Non-paying users can only tick Basic compression, then click on the Choose option to start compression.


Though it’s a free online compressor, Smallpdf allows users to perform two free compression tasks every 24 hours. If you need to compress a PDF file to the smallest size in Smallpdf, you may hit a wall as the “Strong compression” is a benefit exclusive to Pro users.  


Since most users require PDF compression on a regular basis, PDF developers have simplified the process of compressing a PDF to the appropriate size and included extra options for more complex PDF compression requirements.

We hope this information is useful when you need to reduce the size of a PDF. If you have any excellent suggestions or views on how to compress a PDF, please share them in the comments section below.

Common FAQ about Best Online & Desktop PDF File Size Compressors

Q:How do I reduce PDF file size in Adobe?

Adobe Acrobat is a powerful compressor on different operating systems. Users can utilize PDF Optimizer options to reduce the PDF file size.

Step 1: Open a PDF document with Adobe Acrobat DC;

Step 2: Click on the File tab, then choose Reduce File Size or Compress PDF;

Step 3: Select Save to specify the destination folder.

If you need to compress multiple PDFs at the same time, visit this website to compress PDFs with Adobe.

Q:How do I reduce a PDF to 100 KB?

The file size after compression is determined by the file size before compression. If your PDF is larger than 10 MB, the least file size it may become is 3 MB, which is almost three or four times less than the original. For testing, the editor employed a 1.4 MB PDF, and the findings show that the file might be reduced to 0.3 MB or less.



Roche has been an active PDF user for 6 years and tried different types of professional PDF tools (both online and desktop version) since at his bachelor degree. Now, Roche works as a columnist for SwifDoo PDF over the course of the last one year, and provides useful and practical solutions pertaining to various PDF topics for users from different features.