How to compress a PDF for email (without making it unreadable)
Email services reject big attachments. Here's how to shrink a PDF under 10, 5 or 1 MB while keeping text sharp, and what to do when it still won't fit.
· 2 min read
Most email services cap attachments at around 20–25 MB, and many company mail servers set the limit far lower, often 10 MB. Upload forms for jobs, visas and universities can be stricter still, with limits like 2 MB or even 500 KB. The good news: almost every oversized PDF can be shrunk a lot without anyone noticing.
Why some PDFs are so big
A PDF's size comes almost entirely from images. Text and vector drawings take very little space; a 100-page text-only report is often under 1 MB. Big files usually contain:
- Scanned pages, where every page is a full-resolution photo of paper.
- Photos from a phone or camera, embedded at 12 megapixels or more.
- Duplicate or unused fonts and images, left behind by some editing programs.
So compression mostly means re-encoding those images at a sensible resolution and quality.
Compress it in your browser
- Open your PDF. It's processed on your device, so nothing is uploaded.
- Pick Recommended for everyday use, or Extreme for scans and photo-heavy files.
- If you have a hard limit, turn on Compress to a target size and choose it, for example under 1 MB.
- Download the smaller file and check a couple of pages at 100% zoom.
How small can you go?
As a rough guide for typical documents:
| Document | Before | After (Recommended) |
|---|---|---|
| 10 scanned pages | 15–30 MB | 1–3 MB |
| Report with photos | 8 MB | 1–2 MB |
| Text-only contract | 400 KB | 300–400 KB |
Text-only PDFs are already compact, so don't expect big savings there.
When it still won't fit
- Split it. Send the document as two or three emails, or upload just the pages the form asks for. Split PDF can cut it by page ranges.
- Use Strong compression. For very image-heavy files, the Strong option rebuilds the whole PDF on our servers and deletes it within an hour.
- Share a link instead. For files over 25 MB, a cloud storage link is often simpler than any attachment.
A quick checklist before you hit send
- Open the compressed file and read a page of small print.
- Check signatures and stamps are still clear.
- Rename the file to something meaningful, like
Jane-Doe-application.pdf.