Oversized files can fail to upload or take a long time to process or be rejected if they are too large.
You can shrink the file on your computer first. The steps below use tools already built into macOS and Windows. Nothing is uploaded to a third-party website, which is important for private legal documents.
Keep the original file. Always save the compressed copy under a new name so you still have the full-quality scan.
Every Mac includes Preview and a built-in Quartz filter called Reduce File Size. This is the fastest free method and works especially well on scanned PDFs.
Open the PDF in Preview. If another app opens it by default, Control-click the file in Finder and choose Open With → Preview.
In the menu bar, choose File → Export.
Use Export, not Export as PDF. The Quartz Filter menu only appears on Export.
Confirm Format is set to PDF.
Open the Quartz Filter pop-up menu and choose Reduce File Size.
Give the file a new name (for example, Smith-Trust-compressed.pdf) and choose where to save it.
Click Save. If Preview asks whether to replace the original, click Cancel, then save under a different name.
Open the new PDF and check a few pages at 100% zoom. Make sure signatures, handwritten notes, and small type are still readable. If they are too soft, keep the original and try the lighter options below instead of Reduce File Size.
On recent versions of macOS, the Export dialog also includes checkboxes you can use without choosing Reduce File Size:
Optimize images for screen — shrinks images for on-screen viewing
Save images as JPEG — converts embedded images to JPEG, which is effective on scans
Create Linearized PDF — helps the file load faster in a browser; it does not always reduce size much
These usually keep more detail than Reduce File Size. Try them first if the default filter makes pages look blurry.
Reduce File Size downsamples images and compresses them. A large scanned packet can drop dramatically (often by more than half). Text-only PDFs shrink less because they are already compact.
The filter is aggressive. That is usually fine for uploading a working copy. It is not ideal if you need a print-quality archive of the original scan.
Windows does not include a one-click Quartz-style filter. The closest built-in equivalent is to re-print the PDF to a new PDF. That re-renders the pages and often compresses the large scan images.
Open the PDF in Microsoft Edge, Adobe Acrobat Reader, or another PDF viewer.
Press Ctrl + P (or choose Print).
In the printer list, select Microsoft Print to PDF.
Click Print.
Choose a new file name and save location. Do not overwrite the original.
If Microsoft Print to PDF is missing, add it in Settings → Apps → Optional features → Add a feature, then search for Microsoft Print to PDF.
Right-click the PDF and choose Open with → Microsoft Edge.
Press Ctrl + P.
In the printer list, choose Save as PDF (or Microsoft Print to PDF).
Click Save and store the new file under a different name.
Results vary. Scanned, image-heavy PDFs often get smaller. Text-based PDFs may shrink only a little, and sometimes the new file is not smaller.
This method flattens the file. Bookmarks, hyperlinks, form fields, and some metadata are usually removed. For a scan of an old paper document, that is rarely a problem.
Always open the new file and confirm that pages are complete and readable before you upload it.
Acrobat Pro can compress more gently than Print to PDF:
Open the PDF in Acrobat.
Choose File → Save as Other → Reduced Size PDF, or use All tools → Compress a PDF.
Save a new copy and review the pages.
The free Acrobat Reader app does not include this tool.
Compare file sizes in Finder or File Explorer. You want a copy that is small enough to upload, not necessarily the smallest possible file.
Flip through every page. Confirm nothing is missing, rotated, or cut off.
Zoom in on signatures, notary stamps, dates, and handwritten margins.
Upload the compressed copy. Keep the original scan in your own records.
If the compressed file is still too large, repeat the same process on the already compressed copy once. Compressing twice can help on very high-resolution scans, but quality drops each time.
They run on your computer. The document never leaves your machine during compression.
They are already installed on most Macs and PCs.
They target the thing that makes old scans huge: high-resolution page images.
Avoid uploading wills, trusts, or other client documents to random “compress PDF online” websites.
I don’t see Quartz Filter on my Mac.
You chose File → Export as PDF instead of File → Export. Close the dialog and use Export. Format must be PDF.
The Mac file looks too blurry.
Do not use Reduce File Size. Export again and use only Optimize images for screen and/or Save images as JPEG, or upload the original if it is within the size limit.
Print to PDF on Windows did not get smaller.
Try opening the file in Edge and using Save as PDF instead (or the reverse). If the PDF is already optimized text rather than a scan, built-in tools may not help much.
The PDF is password-protected.
Unlock it first (if you are allowed to), then compress. Filters and print-to-PDF often fail on locked files.
Pages turned into one long image and I can no longer select text.
That is normal for scans and for Print to PDF. Uploading a flattened scan is fine for most estate planning packets.
