Compress a PDF for iCloud Mail
iCloud Mail takes PDFs up to 20 MB. PDF Desk shrinks yours to just under it, right in this tab.
Max 20 MB
Files stay on this device. Nothing is uploaded.
iCloud Mail upload limits
| Document | Max size | Min size | Formats |
|---|---|---|---|
| Email message size Up to 5 GB with Mail Drop turned on. | 20 MB | — |
Where this number comes from
“The size of incoming and outgoing messages (20MB, up to 5GB with Mail Drop turned on)”
— Mailbox size and message sending limits in iCloud – Apple Support, 2025-03-17. Checked October 2026.
PDF Desk aims at 19.4 MB, a little under the limit, because some portals count 1 KB as 1,000 bytes.
If the file will not get small enough
Scan in black and white at 150 DPI instead of colour. Remove blank and duplicate pages with Delete pages. If the portal allows several files, cut the PDF with Split PDF and upload the parts.
Other portals in Worldwide (email, messaging, global services)
Limits of other portals
Questions
What is the maximum PDF size for iCloud Mail?
Email message size: 20 MB. Source: support.apple.com, checked October 2026.
iCloud Mail still rejects my PDF. Why?
Check that it is not password-protected, that the file name has no special characters, and that it is a few percent under the limit — some portals count 1 KB as 1,000 bytes.
Are my PDFs uploaded?
No. PDF Desk opens and writes the file with JavaScript inside your browser tab. Nothing is sent to a server, so it is safe for contracts, IDs and bank statements.