How to Shrink a PDF Below the Email Attachment Limit
2026-06-03 · 4 min read
Most email services cap attachments around 25 MB. Here is how to get a bloated PDF under the limit.
You hit "send" and the email bounces: attachment too large. Most providers cap attachments around 20–25 MB, and scanned or image-heavy PDFs blow past that easily. Compression is the fix.
Why PDFs get so big
Text-only PDFs are tiny. The size comes from images — especially scans, which store each page as a high-resolution photo. A handful of scanned pages can balloon a file to tens of megabytes.
How compression works
PDF compression mainly re-encodes those embedded images at a lower resolution and quality. A "medium" setting often cuts file size by half or more with little visible difference on screen.
For documents that will only be read on screen or printed at normal size, a medium setting is plenty. Reserve maximum quality for files going to a professional printer.
Other ways to slim a PDF
- Split out only the pages you actually need to send.
- Scan in grayscale rather than full color when color is not needed.
- Avoid re-saving an already-compressed PDF repeatedly, which degrades quality.
Compress it now
The Compress PDF tool re-renders pages at a quality level you choose and shows the before/after size, so you can get under the limit in one step — without uploading your file anywhere.