PDF files can quickly become too large. Fortunately, many tools can make PDF files smaller and easier to share online. Next time you hit a PDF file size limit, they'll bail you out.

We've compiled the best tools to compress a PDF file into four general categories.

1. Adobe Acrobat Pro

Adobe Acrobat DC Optimize PDF reduce file size menu

If you have Adobe Acrobat installed on your computer, there's a tool within the application called "PDF Optimizer". This is one of the best and easiest ways to shrink a PDF document.

To get to this, open your PDF in Acrobat, and click Tools > Optimize PDF. The Optimize PDF toolbar will appear just above the PDF. If you click Reduce File Size, you can choose to reduce single or multiple files. Next, you'll choose the file location and name. Once you click Save, Acrobat will apply default settings to your file to attempt to reduce its size.

If you click Advanced Optimization, you'll have more options to ensure you maintain the quality you need. To help with this, in the Advanced Optimization window, click Audit Space Usage, and you'll be able to see how much space each kind of element is taking up within the file.

Using the default setting, our sample file shrunk from 11,775KB to only 212KB, making Adobe Acrobat Pro one of the most effective PDF compressors in this list. It's a paid tool, after all, but there was one free tool that performed better with default settings. Adobe Acrobat Pro DC will set you back $14.99 per month, but you can get a 7-day free trial.

2. Browser PDF Tools

TinyWow

TinyWow PDF Compression

TinyWow is possibly one of the simplest browser-based methods to compress a PDF you can use. Simply drag or upload a PDF document to the browser window, and the compressor will work its magic in a matter of seconds. Our sample file was compressed down to 262kB.

Once the PDF file has been compressed, you can download it to your device or save it to a drive like Google Drive. If you want to upload and compress more PDFs, you can click "start over", and the browser will take you back to the upload screen. From here you can upload via PC, mobile, or previous files you have uploaded.

All generated files are deleted within one hour of upload, so you can feel reassured your files won't be stored anywhere for anyone to access.

NeeviaPDF

DocuPub Neevia PDF settings options

If you want more control over the quality of your compressed PDF, try DocuPub's NeeviaPDF (for files less than 24 MB in size). To keep things simple, you can choose one of the presets, which ranges from low compression (for higher image quality) to maximum compression (for lower image quality).

You're also given the option to discard certain elements from within your PDF. This includes things like forms, annotations, and page labels, which can unnecessarily increase the size of the file.

Our sample PDF lost 98% of its size, clocking in at only 203KB, down from 11,775KB. This was the smallest we achieved in our tests, and the result looked just fine. How much of the original PDF you want to discard depends on how much space you really need to save.

3. Windows PDF Tools

Windows 10 finally includes an option to print-to-PDF. However, advanced features, like tweaking the quality and size of a document, are not part of this feature. Meanwhile, many PDF printers let you choose quality and compression settings, which can greatly influence the size of your PDF files.

Soda PDF Desktop

Soda PDF Desktop

Soda PDF is an Adobe Acrobat Pro competitor. While the free version is severely limited, you can compress PDF files when upgrading to the pro plan, which is $110 annually, though you can get up to 65% off when you reload the checkout page. When you first download Soda PDF, you get a 7-day free trial.

Soda-PDF-Desktop-Convert-Compress-Menu-1

To reduce the size of your PDF, open the file, then go to Create & Convert > Compress. This will bring up a menu where you can choose the compression level, from smallest to largest (file size).

At the smallest option, with file compression and image resampling set to 150 dpi, our 11,775MB file got compressed to 261.53KB. That's roughly 98% smaller than the original PDF file, which is on par with Adobe Acrobat Pro. When you install Soda PDF Desktop, it's best to decline any third-party software packed with the installer.

Note that the tools highlighted below require GhostScript to view and handle PDFs.

4Dots Free PDF Compress

4dots Free PDF Compress main window

This freeware application enables you to compress single or multiple PDFs in one fell swoop. You're also able to compress entire folders of PDFs with just a few clicks of the mouse, even if the PDFs are password protected.

Click the Add File(s) button and select the files you'd like to compress. You can select an Output Folder and save a copy or overwrite the old file. The Compress Images option is checked automatically, and you can reduce the image quality further; we went with the default 25% image quality setting.

When you're happy with the setup, hit Compress, and the tool will do all the work for you. Our five sample PDFs took only a moment to compress and came out at 4,593kB or 39% smaller.

Free PDF Compressor

Free PDF Compressor file selection screen

This completely free piece of software is also extremely simple to use. Select the file you want to shrink, hit Compress, then save the smaller file.

In addition, you can choose from five levels of compression, depending on how you want to use the file:

  • Low resolution (72 dpi), ideal for screen-view only
  • Medium resolution (150 dpi), ideal for an ebook
  • High resolution (300 dpi), ideal for printing
  • Prepress (300 dpi), ideal for prepress, including color preserving
  • Default, ideal for a wide variety of uses

Our single sample file was done in less than a minute and, due to choosing the maximum compression level, came out at only 276KB, down from 11,775KB. The final image quality was perfectly fine.

IrfanView

IrfanView is a lightweight and feature-rich image viewer for Windows. It comes with a range of plugins that turn it into a versatile image editing tool, for example, to convert images to different file types, add watermarks to your photos, and batch process images. It also has PDF printing qualities, though not in the classic sense.

Before you can view PDF files with IrfanView, you need to install GhostScript. Then, when you attempt to Save your oversized PDF as a new and smaller PDF file, you'll see a PDF save options window next to your Save PDF As... dialog. Here you can adjust compression settings as seen below.

IrfanView PDF Save Options

In my test, I chose medium quality for all image types and could reduce the size of our 11,775kB sample PDF to 3,359kB. The result was slightly blurred, but perfectly legible.

4. Mac PDF Tools

PDF Filter

compress-pdf-mac

If you routinely update your Mac's operating system, you should be able to shrink your PDF without installing any new apps. This is a cool feature in OS X that many people don't know about.

First, open your PDF in preview. Usually, you can just double-click the file, but if you have a PDF reader such as Adobe Reader installed, you'll want to right-click > Open With > Preview). Then click File > Export, and in the Quartz Filter drop-down box, select Reduce File Size.

This only works with large PDF files. Try doing this with a very small PDF (less than a few MB), and these could actually increase in size.

PDF Squeezer 4

pdfsqueezer

Other than the simple process above, there really isn't much choice for reputable, free PDF compression tools for Mac users. If you want to control the output quality, etc. of your compressed PDFs, your best bet is to download an app such as PDF Squeezer ($9.99).

The app lets you choose from various predefined compression settings, or you can create your own compression profile. You can also batch-process multiple files at once, including entire folders and subfolders.

How Do You Make a PDF Smaller?

This is only the start of what you can do with your PDFs. From reading the text within images and scanning files for malware to converting PDFs to other formats and unlocking password-protected PDFs, you can find the perfect PDF tool to help you.