Compress PDF for Outlook
Fit a PDF under the 20 MB limit of the Outlook desktop app.
Drop a PDF, or choose a file
PDF files of any size.
Your file never leaves your device
Email limits
| What | Official limit | Source |
|---|---|---|
| Outlook.com | 25 MB per file | support.microsoft.com |
| Outlook desktop app | 20 MB total for Outlook.com, Gmail and other internet accounts | learn.microsoft.com |
| Microsoft 365 work accounts | 35 MB per message by defaultYour admin can change it. Includes about 33% encoding overhead. | learn.microsoft.com |
Limits verified Oct 2, 2026 against official sources.
Report an outdated limitWhy files fail on Email
The Outlook app limits internet accounts to 20 MB in total, so a PDF that attaches on the web can fail in the desktop app.
What this preset does
This preset brings the PDF just under 20 MB with room for your message.
Questions
- Why does Outlook say my attachment is too big?
- The desktop app's default limit for Outlook.com and Gmail accounts is 20 MB.
- What about work accounts?
- Microsoft 365 defaults to 35 MB per message, but your admin may set a different limit.
- Can I send a link instead?
- Yes, attach a OneDrive link for files that are still too large.