How to Reduce PDF Size on Mac and Check the Quality

The goal is not always the smallest possible PDF. A document that meets an upload limit but makes receipt totals, diagrams, or scanned text unreadable is not a usable result.

Start with the recipient’s file-size limit and quality requirements. Then choose a compression setting, save a copy, and check both the file size and the content.

Part 1. How to Reduce PDF File Size on Mac with UPDF

UPDF for Mac provides output-quality settings so you can compare file size against readability. Keep the original PDF and test compression on a separate copy rather than assuming the strongest setting will produce the best result.

Step 1. Open the File-Size Reduction Options

Open your PDF in UPDF. Expand the menu beside the Save icon and select Reduce File Size….

Step 2. Choose the Output Quality

Expand Output Document Quality to review the available settings: Uncompressed, Lossless, Maximum, High, Medium, and Low. Start with Lossless when preserving quality is the priority. If the saved file is still too large, compare a lower-quality setting using the original PDF.

Uncompressed is not a size-reduction setting. Lower-quality options may produce smaller files, but check small text and image details before choosing the final copy.

Step 3. Save a Separate Copy

Click Save As, enter a new filename and location, and click Save. Check the saved file’s size and open it again before sharing.

Want to compare these settings on your own document? Download UPDF for Mac and test a copy of your PDF.

The video below provides a cross-platform overview of UPDF compression. For the current Mac interface, follow the written steps and screenshots above. Output quality depends on the settings and the original document.

Part 2. How to Reduce PDF File Size on Mac with Adobe Acrobat

If you already use Acrobat, its Reduced Size PDF command provides a direct way to create a smaller copy.

1. Open your PDF in Acrobat on Mac.
2. Choose File > Compress a PDF.
3. Select the compatibility setting that suits the people receiving the document.
4. Click OK, then save with a new filename to preserve the original.
5. Reopen the saved PDF and check its size and readability.

Do not assume file-size reduction leaves every image unchanged. Refer to Adobe’s current file-size reduction instructions if your interface differs.

Part 3. How to Reduce PDF File Size on Mac with Preview

Preview is built into macOS and can compress a PDF during export.

1. Open the PDF in Preview.
2. Choose File > Export.
3. In the Quartz Filter pop-up menu, select Reduce File Size.
4. Use a different filename to keep the original, then click Save.
5. Reopen the exported PDF and check the result.

The resulting size and image quality depend on the file and export settings. If scanned text or diagrams become unclear, return to the original rather than repeatedly compressing the degraded copy. See the dedicated guide to compressing PDFs in Preview for Preview-specific instructions.

Part 4. How to Shrink PDF on Mac Online

For a file you are permitted to upload to an online service, iLovePDF offers three compression levels: Extreme compression, Recommended compression, and Less compression.

1. Open iLovePDF’s Compress PDF tool and select your file.
2. Choose a compression level and click Compress PDF.
3. Download the result, check its file size, and review the content before sharing.

Start with Recommended compression for a comparison. Extreme compression prioritizes a smaller file over image quality, while Less compression prioritizes higher quality.

Online processing requires uploading the document. For confidential files, follow your organization’s rules before using a third-party service.

Part 5. Meet a File-Size Limit Without Making the PDF Unreadable

A compression preset is not a promise of an exact output size. The result depends on the original document, including its images and existing compression.

Start with the highest-quality setting that may meet your limit. If the saved file is still too large, test a stronger setting from the original and compare the results.

What to Check Before Sharing

1. Fine details: Compare small labels, thin lines, and diagrams. Start with Lossless or a higher-quality option.
2. Upload limits: Check the actual saved file size and confirm that all required pages remain present.
3. Scanned documents: Inspect numbers, punctuation, stamps, and handwriting—not just large headings.
4. Print-ready files: Follow the recipient’s print-quality requirements rather than optimizing only for screen viewing.

Example Workflow: A Scanned Application with a 5 MB Upload Limit

Save two versions from the original using different compression settings. Check both files in Finder, then compare the page containing the smallest text. Choose the clearer version that meets the limit—not automatically the smallest file.

If neither version is acceptable, check whether the recipient allows separate files. Splitting creates multiple documents; it does not compress the same complete document into one smaller file.

Why Is the PDF Still Too Large?

A PDF that has already been optimized may have little room for further reduction. Repeating the same compression process does not guarantee a smaller result.

If stronger compression makes the document unreadable, stop and return to the original. Consider adjusting the source export settings, removing only genuinely unnecessary content, or asking the recipient whether another submission method is acceptable.

Need to compare compression settings on your own document? Download UPDF for Mac and test a copy before sending the final file. Explore the PDF compression features for more details.

Part 6. FAQs on Reducing PDF Size on Mac

Conclusion

Reducing PDF size on Mac means balancing the recipient’s file-size limit with the document’s readability. Keep the original, save a compressed copy, and check the actual output before sharing.

Preview provides a built-in option, while UPDF lets you compare output-quality settings. If the document is already optimized or becomes unreadable at stronger settings, reconsider the source export or submission requirements instead of repeatedly compressing it.

Ready to test a smaller copy? Download UPDF for Mac and compare the result with your original PDF before sharing.