Key takeaways
- Most email services limit attachments to about 20–25 MB; many portals to 1–5 MB.
- Compress PDF › Recommended is usually enough; use Extreme for tight limits.
- If still too big, split the PDF into parts or convert text pages to black and white.
- Check readability after compressing, especially small print and stamps.
"Attachment too large." It's the most common reason a PDF doesn't reach its destination. Here's a quick routine to get any PDF under the limit without making it unreadable.
Know your limit
| Service | Typical limit |
|---|---|
| Gmail | ~25 MB |
| Outlook / Microsoft 365 | ~20 MB |
| Yahoo Mail | ~25 MB |
| Many company mail servers | 10 MB |
| Government and job portals | 1–5 MB per file |
Step 1: Compress
- Open Compress PDF.
- Add the file and choose Recommended.
- Download it and check the size.
Scanned PDFs usually shrink dramatically at this step.
Step 2: Still too big? Go Extreme
Run it again with Extreme. Images are reduced to about 110 dpi, which is fine for on-screen reading. Open the result and zoom into the smallest text to make sure it's still legible.
Step 3: Remove what isn't needed
- Delete blank or duplicate pages with Remove pages.
- Send only the relevant pages with Extract pages.
Step 4: Convert to grayscale
Color scans of text documents waste space. Grayscale PDF shrinks them further — perfect when color isn't required.
Step 5: Split into parts
Still over? Split PDF into two or three files and send them in separate emails, numbered "Part 1 of 3".
What not to do
- Don't zip it. PDFs are already compressed; a ZIP saves almost nothing and may be blocked by spam filters.
- Don't screenshot pages. You lose sharpness and searchable text.
- Don't upload confidential files to unknown compression sites. Osd-Scan compresses in your browser.
Alternative: share a link
For very large documents (manuals, portfolios), upload them to your own cloud storage and email a link. Keep sensitive documents password-protected with Protect PDF.
With these steps, almost any document can be emailed in minutes — and still look sharp when it arrives.
Frequently asked questions
What is the Gmail attachment limit?
Gmail allows about 25 MB of attachments per email. Larger files are sent as a Drive link.
What is the Outlook attachment limit?
Outlook.com and many company servers allow about 20 MB; some companies set lower limits.
How do I get a PDF under 1 MB?
Use Extreme compression, convert text pages to grayscale or black and white, and remove unnecessary pages.
Should I zip a PDF to make it smaller?
Zipping rarely helps, because PDFs are already compressed internally. Compress the PDF instead.