10 Ways to Compress PDF Documents on Desktop and Mobile

The beauty of the PDF format is that you can open it on any platform, be it desktop or mobile. It is easy to create, send, share, read, and edit PDF documents and works everywhere. Unfortunately, some PDF files are too large, which poses problems. This guide discusses those issues and offers a solution: compress PDF documents on Windows, macOS, Linux, Android, and iOS.

Tip: if you’re just looking to edit a PDF document, we can show you how to do so using desktop and online tools.

Drawbacks of Large PDF Documents

There are several issues that occur when you compress PDF documents. Some of the most common are:

• Can’t attach large PDF files to email, as most email service providers, like Gmail, have a 25MB attachment limit.
• Can’t attach large PDF files to messaging apps like WhatsApp, as it has a 16MB limit.
• Takes longer to upload and download, especially on a slower bandwidth and under certain situations, like traveling in remote areas.
• Consumes more bandwidth, which can be a problem on metered connections like smartphones or carrier data plans.

1. Adobe PDF Compressor (All Platforms)

Since Adobe developed the PDF file format, it makes sense that Adobe would also have a free tool available to compress the file. The Adobe PDF Compressor is free for files up 2 GB. Otherwise, it’s $14.99/month. The tool is completely online, so it’s compatible on all platforms as long as you have an Internet browser.

1. Open your favorite browser and go to the Adobe PDF Compressor site.
2. Click “Select a file” and choose the PDF document you want to compress.

3. Choose your compression level. The less compression, the higher quality the file. For PDFs with many images, you may want to choose “Low.” However, I compressed a PDF magazine I had purchased as a test using the highest compression level and had no issues.

4. Press “Compress” to compress your file and wait for the process to complete.

5. If you already have an Adobe account (which is free), sign in to download your file. You can also create a free account to download the file. You’re free to delete your file as soon as you download it.

There was significant compression: 139.81 MB down to 24.76 MB.

Tip: there aren’t native Linux options for all Adobe apps. Find out how to install Adobe Creative Cloud apps in Linux.

2. iLovePDF (Windows, macOS, iOS, Android)

iLovePDF has both online and desktop options. The desktop version is free for up to five tasks. However, these tasks can include a large number of PDFs in one task. As long as you add them all to the same task, it just counts as one session. The desktop version only works on Windows and macOS, and there are mobile apps for iOS and Android. However, you can use the online version on any platform with a supported browser, though it does work slower.

The free version is limited, but if you need to use it frequently, it’s $48/year.

For this example, I’m using the Windows desktop version, but all of the versions work similarly.

1. Open iLovePDF and select “Compress PDF” from the tools list.

2. Select “Open File” and choose your file(s). Remember: you can compress multiple PDFs at one time.

3. Select your compression level and press “Compress PDF.”

4. Wait for the process to complete. It can take several minutes or more for a file over 100 MB. At the recommended medium compression level, it took my 139.81 MB file down to 45.82 MB.

3. NXPowerLite (Windows / macOS)

NXPowerLite is a premium-only option that offers a full 14-day free trial (up to 19 files) without a credit card. After the free trial, it will cost a one-time fee of $49, with no subscription necessary. It works on both Windows and macOS.

1. After downloading NXPowerLite, add your file(s). Either click “Add Files” or drag and drop your file(s) into the open area. A variety of common file types are supported beyond PDF, such as JPG, PPT, and DOC.

2. Click “Optimize.” You can change preferences and settings by going to “Edit -> Preferences.”

3. Wait for the compression to complete. It’s one of the faster options on the list.
4. Review the details and check out your compressed PDF file. It took my 143,170 KB file down to 68,726 KB.

FYI: need to sign your PDF document? Learn how to do it on your Mac.

4. Preview (native macOS option)

While Preview provides a native option to reduce the file size when exporting a file as a PDF, the results are often less than satisfactory. You can use filters such as Quartz Filters to get better results. It adds additional filters to the default filters that Apple offers in Preview to reduce PDF file size. Quartz is also more consistent with the quality and size of the files compressed.

5. Lightweight PDF (macOS)

Lightweight PDF is as simple as it gets. Add your file and let it compress. That’s all there is to it.

1. Install and open Lightweight PDF and drag and drop the PDF file you want to compress in macOS.

2. The compression process will begin immediately. There are no buttons to press or options to select. Note that the new compressed file will overwrite the existing file, so you may want to create a copy first.

3. When the process is complete, the app will display the results.

Good to know: working with scanned documents? Learn how to combine scanned documents into a PDF on macOS.

6. PDF Shrink (macOS)

PDF Shrink works like Lightweight PDF but with one notable difference: when you drop the PDF file, it lets you select the quality and resolution of the output. You can play around with these values to find a balance where files are compressed with minimal quality loss. However, it’s not free and costs $2.99.

Unlike Lightweight PDF, it will ask you to choose a download location instead of overwriting the existing file.

7. Ghostscript (Linux / Windows)

Ghostscript lets you manipulate PDF files. One of the tools includes a PDF compressor.

1. Open the Command Line tool, also known as the Terminal. If you don’t know how to do that, click on the Ubuntu icon to open Dash and type Terminal to search and open it.

2. Use the command below to install Ghostscript.

sudo apt install ghostscript

3. The command below will reduce the size of the PDF file. Note that you will need to change the name of the PDF file in the command accordingly. In my case, the file was saved in the Downloads folder. Make sure the path is correct, too, as it won’t be able to detect the PDF file to compress it.

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed_PDF_file.pdf input_PDF_file.pdf

In the example above, the input file was 4MB.

And the output file was just 235KB.

The tool’s also available to use in Windows.

Tip: learn how to remove the password from a PDF in Linux.

8. Densify (Linux)

Densify is open source, hosted on GitHub and uses Ghostscript.

1. Open the app to be greeted with a simple GUI. Select the PDF file you want to compress and select a Type. If unsure, choose “Screen” or play around with different options until you get a satisfactory result.

2. Click the “Compress Now” button.

3. You will get a notification when the PDF file is compressed.

This quick chart explains the different compression types Densify has to offer and what they mean for your reference.

9. Compress PDF File (Android)

Compress PDF File is a completely free tool (with ads) and one of the highest-rated options to compress PDF documents in the Play Store. While there are a few settings, it’s a straightforward app for any Android user.

1. After installing Compress PDF File, tap on “Open PDF” to choose a file.

2. Select your compression level and tap “Compress.” Recommended usually does well for most users, though.

3. Wait for the file to compress.

4. After reviewing the compression details, choose whether to save your file or start again with a different compression level.

Good to know: need quick access to your PDF files? This tutorial shows how to add a PDF shortcut to your home screen on Android and iPhone.

10. PDF Compressor (iOS)

PDF Compressor works like its Android counterpart.

1. Tap on the “Select PDF” button to choose the PDF document. Select one of the compression settings, then tap on “Compress PDF.”

2. You should see a pop-up with details of the compression. The compressed file can be found under the “Compressed” tab.

Drawbacks of Compressing PDF Documents

Throughout this tutorial, you can see the need to compress PDF documents and how we can compress PDF files on various desktop and mobile operating systems. But there are also drawbacks of compressing PDF files:

• Not all tools are free. Some are paid and others adopt the freemium model.
• Compressing PDF files too much can reduce the quality of included images, ruining the experience for the reader.
• Too much compression can also break text and other elements, rendering the PDF file unreadable.

Frequently Asked Questions

Image credit: Pixabay.

Crystal Crowder - Staff Writer

Crystal Crowder has spent over 15 years working in the tech industry, first as an IT technician and then as a writer. She works to help teach others how to get the most from their devices, systems, and apps. She stays on top of the latest trends and is always finding solutions to common tech problems.