RapidHow to Compress a PDF on Mac — Free, No Upload
Two free ways to make a PDF smaller on a Mac, step by step: a browser tool with three levels, and Preview’s built-in filter.
⚠️ Always use a copy of your document, never the original. Keep your original file safe.
How to compress a PDF on Mac has two free answers. The simplest is to open our free Compress PDF tool in Safari or Chrome, choose a level and download the smaller file. It runs in your browser, so there is nothing to install and your PDF stays on your Mac. The built-in option is Preview: choose File > Export and pick the Reduce File Size Quartz filter. Preview has only one setting, and it can make text and pictures blurry or barely change the size.
This guide covers only the Mac. For other devices and other methods, such as saving a smaller PDF from Word, see the main guide: how to compress a PDF.
Method 1: Compress PDF in Your Browser (Simplest)
This works in Safari, Chrome, Firefox and Edge on any Mac. The PDF is read and compressed by your browser on your own Mac. It is not sent to a server.
- Open rapidtools.online/compress-pdf. No account is needed.
- Drag your PDF into the box, or click the box and choose the file in Finder.⚠️ Always use a copy of your document, never the original. Keep your original file safe.
- Choose a level: High Quality (keeps images sharp), Medium (a good balance) or Maximum (smallest file, lower image quality).
- Click Compress PDF. The tool shows the original size and the new size.
- The smaller file downloads by itself, with “-compressed” added to the name (for example report-compressed.pdf). In Safari, it goes to your Downloads folder unless you changed that setting.
The tool shrinks only the images inside the PDF. Text, fonts and drawings are not changed, so text stays sharp and you can still select and search it. If compressing does not make the file at least 1 percent smaller, the tool keeps your original, does not download a new file, and tells you so.
Real test results
Three test PDFs compressed with this tool on the Medium level:
| Test PDF | Original | After Medium | Smaller by |
|---|---|---|---|
| PDF with photos | 15.58 MB | 553 KB | 97 percent |
| Scanned PDF | 8.77 MB | 1.95 MB | 78 percent |
| Text-only PDF | 16.5 KB | 12.9 KB | 22 percent |
The same scanned PDF became 54 percent smaller on High Quality and 92 percent smaller on Maximum. These are typical results, and your files will be different. PDFs with photos or scans shrink the most. A PDF that is mostly text is already small and shrinks very little.
Method 2: Compress a PDF With Preview (Built In)
Preview comes with every Mac. Its Reduce File Size option is a Quartz filter, a setting that is applied when the PDF is saved.
- Open the PDF in Preview. If it opens in another app, Control-click the file in Finder and choose Open With > Preview.
- Choose File > Export.
- Make sure Format is set to PDF.
- Click the Quartz Filter menu and choose Reduce File Size.
- Type a new name, such as report-small, so you keep the original, then click Save.
- Open the new file and zoom in to check that the text and pictures are still clear. In Finder, compare the two file sizes.
Known Problems With Preview’s Reduce File Size
Preview works well for some files, but it has known problems. Apple says only that the result may be of lower quality and that size and quality vary. Mac users report these problems on Apple’s own support forum:
- Only one setting. You cannot choose a light or strong level. The same filter is used for every file.
- Blurry text and pictures. The filter shrinks the pictures in the PDF a lot, and it can shrink them too much. Scanned pages are pictures, so their text can become hard to read.
- Little or no size change. On some PDFs, such as files that are mostly text or already compressed, the new file is barely smaller, or not smaller at all.
- Whole file only. The filter is applied to every page. You cannot keep one page sharp and shrink the rest.
If Preview makes the file blurry, use the browser tool on High Quality or Medium instead. For more control on a Mac, you can make your own filter in ColorSync Utility, an app that also comes with every Mac. The main guide shows how: compress a PDF with ColorSync Utility.
Which Method Should You Use?
| Browser tool | Preview | |
|---|---|---|
| Install | None | None (built in) |
| Levels | 3 (High Quality, Medium, Maximum) | 1 (Reduce File Size) |
| Text | Not changed | Can become blurry |
| File leaves your Mac | No | No |
| Keeps your original | Yes, adds “-compressed” | Yes, if you save a new name |
Need the file under an exact size, such as 2 MB or 10 MB? See how to compress a PDF to a specific size. If your PDF is a scan, see how to reduce scanned PDF size.
Frequently Asked Questions
How do I compress a PDF on a Mac for free?
Open rapidtools.online/compress-pdf in Safari or Chrome, choose the PDF, pick High Quality, Medium or Maximum and click Compress PDF. The smaller file downloads by itself. You can also use Preview: choose File > Export, pick Reduce File Size in the Quartz Filter menu and save.
Why does Preview make my PDF blurry?
Preview’s Reduce File Size filter shrinks the pictures in the PDF a lot, and it has only one setting. Scanned pages are pictures, so their text can become blurry too. Try the browser tool on High Quality or Medium instead.
Why did Preview not make my PDF smaller?
Preview’s filter mainly shrinks pictures. If the PDF is mostly text or was already compressed, the new file can be barely smaller, or not smaller at all. Removing pages you do not need with Split PDF can help more.
Is my PDF uploaded when I use the browser tool on a Mac?
No. The PDF is compressed by your browser on your own Mac and is never sent to a server.
How much smaller will my PDF get?
It depends on what is inside the PDF. In our tests on Medium, a PDF with photos became 97 percent smaller, a scanned PDF 78 percent smaller and a text-only PDF 22 percent smaller. These are typical results, and your files will be different.