How to make a PDF smaller for email

4 min read · Updated November 1, 2026

“Attachment too large.” Usually the culprit is a scan or a handful of phone photos. Here’s how to shrink a PDF until it fits.

Why PDFs get big

Text barely takes up any space: a 50-page report can be a few hundred kilobytes. Images are what make PDFs heavy. A modern phone photo is 12 megapixels or more, so a five-page “scan” made from photos can easily be 20 MB or larger.

How small does it need to be?

Gmail accepts attachments up to 25 MB, and many other email services have similar limits. Job portals, school systems and government upload forms are often stricter, commonly 2 to 10 MB. Check the limit before you start.

Pick the right level

• Light keeps text sharp and selectable. It tidies the file’s structure, which helps files exported inefficiently by other tools. Savings are modest.
• Strong redraws each page as a 120 dpi image. For scans and photos this typically cuts the size by 70 to 90 percent while staying easy to read and print.
• Smallest uses 90 dpi. Use it when you’re up against a hard limit.

The Compress PDF tool shows the before and after size before you save, so you can try a level and step down if needed.

Other ways to save space

• Delete pages you don’t need. Blank backs of scanned pages are common. Use Delete pages.
• Split it. Send a long document in two emails with Split PDF.
• Crop your photos first. Before turning photos into a PDF, crop out the table and background around the paper.