# Compress PDF — Compress a PDF on Mac

Shrink image-heavy PDFs for email and upload. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: PDF. Runs on your Mac; nothing is uploaded.

Re-save the images inside a PDF at screen quality as JPEG, which often makes scanned and photo-heavy PDFs several times smaller.

Page: https://www.onemactools.com/tools/compress-pdf · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Add the PDFs.** Drop one or more PDFs onto Compress PDF. Or select them in Finder, right-click and choose Quick Actions › OMT: Compress PDF.
2. **Click Compress.** There's nothing to set. The images inside each PDF are re-saved at screen quality.
3. **Compare the sizes.** Copies ending in “compressed” are saved in a dated folder in Downloads › OneMacTools. Use Show in Finder to see the new sizes next to each other.
4. **Check the pages.** Open the copy with the Preview (eye) button and zoom into a photo or scan to make sure it's still clear enough for your needs.

## Options
- **No options:** Compress PDF has nothing to set. It re-saves the images in the PDF as JPEG at a resolution suited to screens, and leaves text as text.

## Tips
- Compression helps most with scans and photo-heavy PDFs. A PDF that's mostly typed text is usually small already and may barely change.
- Keep the original for printing. Screen-quality images are fine for email and reading, but can look soft on paper.
- If the file is still over an upload limit, use Split PDF with By file size to break it into parts under 2, 5, 10 or 25 MB.
- Compress after merging, not before, so you only do it once on the final document.
- For scanned paperwork you'll keep, run Make PDF Searchable as well, so the smaller file can also be searched.

## Questions
**How do I reduce the size of a PDF on a Mac?**
Drop it onto Compress PDF and click Compress, or use the Finder Quick Action. Images inside are re-saved at screen quality, which is where most of the size usually is.

**Why are some PDFs so big?**
Usually because of scans and photos saved at print resolution. Compress PDF re-saves those images at screen quality, which often makes the file several times smaller.

**Will the text stay sharp and searchable?**
Yes. Text stays as text; only the images are re-saved.

**Why didn't my PDF get any smaller?**
It's probably mostly text or already compressed, so there's little to shrink. Compress PDF works on the images inside a file.

**My PDF has to be under a size limit.**
If compressing isn't enough, Split PDF can break it into parts under 2, 5, 10 or 25 MB.

**Can I choose the compression level?**
No. Compress PDF uses one setting tuned for screen reading and email, so there's nothing to get wrong.