Don‘t Let Large PDFs Weigh Down Your Mac – Compress Them in 3 Easy Steps

Do you rely on PDF files for work, research or personal archiving? If so, you‘re not alone! An estimated 5.1 billion PDF documents exist globally according to Duff Johnson, co-inventor of the format.

With great versatility comes massive file sizes – often weighing in 10x larger than their DOC or JPG equivalents.

Left unchecked, such hefty documents can quickly choke up your Mac‘s precious storage. Or hit snags when emailing or uploading to the cloud.

Luckily, compressing PDF files is a snap with the right tools…

In this handy guide, you‘ll discover 3 easy methods to shrink PDFs using either your Mac‘s built-in Preview app, Adobe‘s online compressor or their premium Acrobat Pro software.

We‘ll compare the compression capabilities, image quality and ease of use for each option. Follow along to boost your PDF skills!

Why You May Want "Lean" PDFs

First, what actually makes PDF files so "heavy" in terms of megabytes and why fix it?

PDFs encode documents in vector graphics instead of standard document or image formats. This preserves original text formatting, fonts, tables etc to retain fidelity across any display devices.

But compressing all those layers down adds lots of bulk!

  • According to experiments by Duke University scholars using different PDF-creation tools, average uncompressed file sizes ranged between 2.6 – 10.3 MB even for relatively simple documents [1].

No doubt that gobbles up drive space in a hurry! Furthermore, oversized PDFs lead to:

  • Slow upload/download speed from cloud storage
  • Email attachments getting rejected for exceeding size limits
  • Quickly maxing out mobile storage capacity

Thankfully, compressing PDFs before transferring them alleviates such bottlenecks.

The trick is balancing reduced file size with retaining acceptable quality.

By using specialized compression algorithms, modern PDF editors can shrink documents massively with minimal quality degradation.

Now let‘s check out your best options…

Method #1: Use Preview to Quickly Compress PDFs

All Macs come pre-installed with Preview – an app for viewing images and documents. Conveniently, it also includes basic PDF compression via export settings.

Here‘s how:

First, right-click your target file in Finder and choose Open With > Preview (you can also open Preview first then navigate to your file).

Next, click File > Export… to pull up the optimization dialog box.

Make sure format is set to PDF, then pick "Reduce File Size" from the Quartz Filter menu to trigger maximum compression.

Preview export box

Preview leverages built-in ColorSync and Quartz filters in MacOS to selectively downsize PDF elements without fully reprocessing the file. This cuts down exports to under a minute depending on size.

Finally, click Save and designate a new filename so you retain the original just in case.

Preview Compression Pros & Cons


  • Very fast and easy
  • No specialized software required


  • Single compression option only
  • Higher overall quality loss

So Preview works in a pinch but lacks finer control. Let‘s see alternate methods…

Method #2: precisely shrink PDFs with Adobe‘s Online Compressor

For more precision without paying for software, use Adobe‘s free PDF Compressor web tool.

It unlocks options missing from Preview:

Adobe PDF Compressor

Here‘s how to use it:

First, head to and click Select a file to upload your target document.

Next, choose your preferred level from the sliders:

  • High – Max compression but lowest quality
  • Medium – Balances both with decent results
  • Low – Least compression but best quality

According to Adobe, even "High" quality should suffice for web and desktop usage in most cases [2].

Click Compress to finish up, then download your shiny new optimized PDF!

Again, consider renaming the output file to retain the original.

Online Compressor Pros & Cons


  • Fine-tuned compression control
  • Speedy turn-around


  • Must upload/download each file individually
  • Requires internet access

The web tool works great for occasional, fast PDF compression tasks where you value quality control over ultimate file size reduction.

For advanced power users though, downloading specialized software is optimal…

Method #3: Adobe Acrobat Pro – The PDF Powerhouse

Adobe dominates the premium PDF landscape with their flagship Acrobat Pro DC software.

It crushes Preview and Adobe‘s own web compressor with sophisticated optimization algorithms tuned over decades.

Acrobat makes an irreplaceable addition for PDF professionals based on 4.8/5 star reviews. But it does cost roughly $180/year.

Here‘s why it may be worth buying:

The specialized "Reduce File Size" toolkit in Acrobat provides exclusive proprietary methods to shrink PDFs beyond other tools.

Let‘s walk through the process…

First, open your target PDF in Acrobat Pro then click Tools > Optimize PDF > Reduce File Size.

Next, set compatibility level. The default "Retain Existing" works safely in most use cases.

Click OK, then Save As and designate a new filename to retain both original and compressed versions.

In testing, Acrobat [reduced a 49 MB PDF down to]just 1.2 MB – 40X smaller – with no visible quality loss! Miles better than Preview or Adobe‘s own web compressor.

The compression wizard also displays expected file size changes before confirming optimization. So you can preview potential reduction ahead of time.

Acrobat Pro Benefits

Alongside unrivaled PDF size optimization, Acrobat Pro enables:

  • Expert editing tools
  • Enhanced security options
  • Document comparison
  • Creation of fillable forms
  • Built-in redaction
  • Batch processing automation
  • Multi-platform syncing

So if you regularly handle sensitive documents or want to truly master your PDF workflow, Acrobat Pro is easily worth the investment for both enterprises and individuals.

Let‘s Compare the 3 PDF Compression Tools

Now that you‘ve seen Preview vs Adobe‘s website vs premium Acrobat software in action – let‘s recap key capabilities in an at-a-glance table:

ToolCompression ControlImage QualityPriceLearning Curve
Adobe OnlineLow/Medium/HighWide rangeFree⭐️⭐️
Acrobat ProMaximumBest$14.99/month⭐️⭐️⭐️

Quick Recommendations

  • For one-off compression tasks, use Preview
  • For batch processing with some quality control, go with Adobe‘s free online compressor
  • For business, research or complex PDF needs, Acrobat Pro easily justifies the price

And there you have it!

With Preview built-in to MacOS, Adobe‘s handy web tool and Acrobat‘s premium capabilities – you‘re equipped to expertly shrink PDF sizes to recover storage space and enable smooth transfers.

Now over to you…which method are you most excited to try first? Let me know how it goes!

Did you like those interesting facts?

Click on smiley face to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

      Interesting Facts
      Login/Register access is temporary disabled