How to Reduce PDF Size Manually [3 Effective Solutions]

Having become the most used document format for information distributions, the document format PDF is used zillion times globally every single day. PDF documents can always inevitably become large in file size, given they contain both textual and visual data. However, the size of PDF documents has always been a major concern for office workers whenever it comes to Email attachments, electronic submissions, and online transmissions.

Today in this post, in a bid to help you make your documents smaller, we’ll talk about how to reduce PDF size manually on PC, Mac, and online. 3 effective methods suitable for different devices and scenarios have been provided for you to choose from, and I’m sure there’s one that fits you. Now, let’s get started.

Method 1. How to Reduce PDF Size Manually Using Adobe Acrobat

Adobe Acrobat is the mainstream PDF reader program from Adobe, the very creator of PDF document format. Apart from PDF reading, Adobe Acrobat also helps to reduce PDF file size on Windows and Mac computers.

But please note that PDF compression is an advanced feature in Adobe Acrobat. This method only works with Adobe Acrobat DC and Adobe Acrobat Pro DC, while the uses of which require paid subscriptions starting at $14.99/mo.

  1. Launch Adobe Acrobat DC or Adobe Acrobat Pro on your computer.
  2. Click File from the menubar and hit the Open option from the dropdown to open the PDF document you want to compress in Acrobat.
  3. Hit the upper-left Tools tab to enter the Acrobat tools section, and then hit the Optimize option within the Protect & Standardize category.

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Acrobat Optimize PDF

  1. From Optimize PDF menu, hit the Advanced Optimization button.
  2. In the pop-up Advanced Optimization window, you can manually reduce PDF file size from color, grayscale, monochrome image compression, and image downsampling – See official explanations(No-follow).
  3. When ready, hit OK to save and export the optimized PDF document from Acrobat.

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Acrobat Advanced Optimization

As mentioned, you need to pay for the subscription to compress PDF with Adobe Acrobat.

Then is it possible to compress PDF size manually online for free? The answer is positive, please read on to learn more.

Method 2. How to Reduce PDF Size Manually Online Free with PDFgear

To manually compress PDF for free, we’ll be using the online PDF compressor tool PDFgear. PDFgear is a free online PDF tool for an extensive range of PDF management purposes, you can make, edit, convert, compress, eSign, split, merge your PDF documents with PDFgear, and there’re tons of other features waiting for you to find out.

With PDFgear free online PDF compressor tool, you get to significantly reduce PDF size with one click, without quality loss. PDFgear works on Windows, Mac, Linux, Chromebook, laptops, iOS, Android, etc. Now follow the tutorial and get started on your own device!

Step 1. Upload Your Documents to PDFgear

Navigate to the PDFgear PDF compressor tool. Hit the Choose files button or drag and drop your files, to upload the PDF documents you intend to manually resize.

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Step 2. Manually Compress PDF Using PDFgear

Select the desired one from the three given compression modes: Low compression, Medium compression, and Strong compression. The higher the compression, the smaller the file size, yet the poorer the output quality.

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Step 3. Download the Compressed PDF Documents

The compression will be done in 2 seconds, when the file is ready, you’ll see the new size of it underneath its filename. Hit the blue Download button to download the compressed file.

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Method 3. How to Reduce PDF Size Manually on Mac Using Preview

If you’re running a Mac computer or Macbook, then there’s a hidden inbuilt option available for you to compress PDF manually on Macintosh – without the need of using any external service or third-party software installation.

The hidden option I referred to, is the PDF reader application Preview preinstalled on Mac devices. In the following, you’ll learn about the detailed steps to manually reduce PDF size on Mac using the Preview app.

  1. Launch Preview app on your Mac device.
  2. Open the PDF document you intend to compress in the Preview app.
  3. Go to the File tab, and then hit Export.
  4. Select PDF as the output file format.
  5. From the Quartz Filter menu, select Reduce File Size.
  6. Click the Save button to save the compressed PDF document.

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Manually Compress PDF Using Preview

How to Compress PDF Manually: FAQs

How do I reduce the size of a PDF file so I can Email it?

In light of the Email attachment size limit, PDF document files used as Email attachments should not exceed 10 MB, generally speaking. And with the PDFgear online PDF compressor tool, you can easily reduce PDF file size to 500 KB or less, without losing quality.

How to reduce PDF file size without losing quality?

To reduce PDF file size without losing quality on PC, Mac, and mobile, you need the free online PDF compressor tool PDFgear. With PDFgear PDF compressor low compression mode, you can easily reduce the size of PDF documents without losing quality.

How to manually reduce PDF file size?

There are several ways of manually reducing PDF file size. The recommended solutions include using Adobe Acrobat Pro (if you have a subscription), and using the free online PDF compressor tool

How long does it take to reduce pdf size using PDFgear?

For normal PDF documents with a size of 0.5-10MB, the online PDF compressor tool takes about 2 seconds to process and compress the file, and then the compressed document will be available for you to download.

Which operating systems are supported?

PDFgear is a cross-platform PDF compressor that allows you to compress PDF files on Windows 10, Windows 11, Mac, Linux, Chromebook, laptops, and mobile phones.

Does PDFgear work on mobile phones?

Yes, PDFgear is a cross-platform online service that works on Windows, macOS, Linux, Android phones, and iOS phones. On your mobile phone, you can access PDFgear from: and convert/compress/edit your PDF documents with ease!

Is PDFgear safe?

PDFgear is a completely safe and clean service. PDFgear is TSL encrypted and PDFgear does not save your files. Upload files will be permanently deleted once the browser is shut down.

Do I keep the original file?

Yes, when compressing PDF files on PC or mobile with PDFgear, your original file stays intact, you get to keep the original file.


In conclusion, Mac users are offered a handy approach to reducing PDF size. And on PC, if you already have an Adobe Acrobat Pro subscription, you can easily learn from the instructions above to optimize PDF size with it. But if you don’t, then I believe PDFgear is the ideal option for you to manually reduce PDF size.

As you can see from the tutorials, in the PDFgear PDF compressor tool, three compression options are offered for you to flexibly compress your PDF documents – from compressing PDF without quality loss, to significantly reducing your document size. I personally find it really practical, so please don’t forget to give PDFgear a try when you have time!