How to Reduce PDF Size on a Mac for Free

To reduce PDF size on a Mac, open the PDF in Preview, choose File > Export and pick Reduce File Size from the Quartz Filter menu. For more control, use ToolistHub's free Compress PDF, which offers Normal and Strong modes with three quality levels. Compress PDF works in your browser, so the PDF is not uploaded.

Reduce PDF size on a Mac with Preview

1. Open the PDF in Preview.
2. Choose File > Export.
3. Choose Reduce File Size from the Quartz Filter menu.
4. Save under a new name, so you keep the original.

Apple's guide to reducing the size of a PDF in Preview also lists export options such as Optimize images for screen and Save images as JPEG, and warns that the compressed PDF may be of lower quality than the original. Open the new file and zoom in before you send it.

Reduce PDF size with Compress PDF

1. Open Compress PDF in your browser and add the PDF with Choose a PDF file. It takes one PDF of up to 50 MB.
2. Choose a mode. Normal, the default, saves photos and scans again as smaller JPEGs and keeps the text, links, bookmarks and form fields. Strong turns every page into an image, which shrinks scans further, but the text can no longer be selected or searched.
3. Choose a quality: Low for the smallest file, High for the sharpest images, Medium in between.
4. Select Compress PDF. You see the size before and after and the percentage saved, then download the copy, named after your file with -compressed added.

If the copy isn't at least 1% smaller, Compress PDF keeps your original instead. That happens with PDFs that are mostly text, because text already takes little space.

Which one to use

• Preview is built in and quick. Apple notes the result may be of lower quality, so check it before you send it.
• Compress PDF lets you choose Low, Medium or High quality, and its Normal mode keeps text selectable. Strong mode works on PDFs of up to 200 pages.

If the PDF is still too large to email, remove pages you don't need with Delete PDF Pages. Our guide to PDFs too large to email covers more ways to send a big file.

Frequently asked questions

How do I make a PDF smaller on a Mac without losing quality?

Every compression trades some image detail for size. Compress PDF's Normal mode at High quality keeps text and drawings unchanged and only saves photos and scans again, which keeps the visible loss small.

Why didn't my PDF get smaller?

PDFs made mostly of text are already compact, so there is little to remove. Compression helps most with scans and photos.

Is Compress PDF free on a Mac?

Yes. It needs no account and adds no watermark, and it runs in your browser.

Conclusion

On a Mac, try Preview's Reduce File Size filter first, and use Compress PDF when you want to choose the quality or keep the text selectable. Check the result before you send it.