How to compress a PDF on a Mac

Three ways at a glance

Compress a PDF with Preview (built in)

1. Open the PDF in Preview.
2. Choose File › Export.
3. In the Quartz Filter menu, choose Reduce File Size.
4. Give the file a new name so your original stays as it is, then click Save.

What it does. Reduce File Size is a single preset. Every image is resampled to 144 pixels per inch at the size it’s shown on the page, up to 2400 pixels, and usually re-saved as JPEG. Text and vector shapes are left alone: in our test, the text came out identical.

Depending on your version of macOS, the Export window also has checkboxes such as Optimize images for screen and Save images as JPEG; Apple lists them in its Preview guide. We tested the Reduce File Size filter only.

Where it does well. It’s already on your Mac, it handles a password-protected PDF once you type the password, and it keeps your text sharp. On our 42 MB demo deck, it made a 14.2 MB file.

Where it falls short. It doesn’t check the result. On our scanned letter, Reduce File Size turned 367 KB into 1.9 MB, and a 49 KB text report came out at 82 KB. And the filter is one preset: you don’t choose a lighter setting for email or a sharper one for print, and you don’t see the size before you save.

Compress a PDF from the right-click menu with Shortcuts

macOS has a Shortcuts action called Optimize File Size of PDF. Build a shortcut around it, turn on Use as Quick Action, and it shows up when you right-click a PDF in Finder. It has no settings. Apple says it compresses the images inside the PDF, and that if they’re already compressed, it might not make a measurable difference. We haven’t measured it.

For more control, Automator’s Apply Quartz Filter to PDF Documents action can run a filter you build yourself in ColorSync Utility, with the resolution and JPEG quality you pick. It takes some setting up, and it doesn’t check the result either.

The right-click way

Compress a PDF with Ricly

1. Install Ricly and open it. Turn on the Finder extension when it asks (one setting), then create your free account and verify your email.
2. In Finder, right-click the PDF and choose Ricly › Compress PDF.
3. Ricly measures your file and shows the exact size of Screen (for email and the web) and Print, plus other sizes it has measured. On a big PDF, that takes a few seconds. Click one: the lighter copy lands next to the original.

What our test showed.

The same area of our demo deck at 200% zoom. Photos in the test deck: Unsplash.

• Preview’s Reduce File Size is one preset. Ricly gives you two, Screen and Print, plus other sizes it has already measured on your file.
• Our 42 MB demo deck: 14.2 MB with Preview, 11.4 MB with Ricly Screen. At 200% zoom, you can’t tell them apart.
• Need it for print? Ricly Print keeps images at 220 pixels per inch. Preview’s preset stops at 144.
• The size Ricly shows before you click is the size you get, to the byte.
• If Ricly can’t make it smaller, it tells you and keeps your original. It never hands you a bigger file.
• On another scan in our test, Screen made it 65% lighter; Print kept the text crisper.
• Your text stays text: selectable and searchable. Your originals are never touched.
• Everything happens on your Mac. Nothing is uploaded.

Where it falls short. It doesn’t open password-protected PDFs: it asks you to remove the password first. The Free plan covers 5 PDFs a month, and a batch that goes over is refused before it starts. It needs macOS 13 or later.

Download for MacSend it to my Mac 5 PDFs a month free · macOS 13 or later · Notarized by Apple

Compress several PDFs at once

With Pro, select ten PDFs, right-click once, choose once. About a second later, ten lighter copies sit next to the originals. In a batch, you pick Screen or Print once; the exact sizes are shown when you compress one PDF at a time.

Can you compress a PDF without losing quality?

Not entirely: making a PDF smaller means giving something up. What you give up depends on what’s inside it.

• Text comes through unchanged. Your text stays text: selectable and searchable. In our test, the text came out identical with Preview and with Ricly.
• Images are what gets smaller. Preview’s Reduce File Size resamples every image to 144 pixels per inch at the size it’s shown on the page. Ricly gives you two settings: Screen, for email and the web, and Print, which keeps images at 220 pixels per inch.
• Compare before you send. On our 42 MB demo deck: 14.2 MB with Preview, 11.4 MB with Ricly Screen, and at 200% zoom you can’t tell those two apart. On a scan, Screen makes it much lighter; Print keeps the text crisper.

To keep the most detail: choose Print in Ricly, keep the original, and zoom to 200% on a photo before you send anything important. Preview keeps your text sharp too; the difference is the choice of setting, and the safety net: if Ricly can’t make a file smaller, it tells you and keeps your original.

Which one should you use?

How we tested. On macOS 15.7, with test PDFs we made ourselves from free stock photos. We applied Preview’s own Reduce File Size filter to the same files, measured sizes in bytes on disk, and compared sharpness at 200% zoom.

Compressing PDFs on a Mac: common questions

Compress PDF in Ricly →Merge PDFs on your Mac →Send it as a link →

Coming from iLovePDF or Smallpdf? See how Ricly compares.