Compress PDF for Outlook
Fit Outlook's 20 MB attachment ceiling. Locally, in your browser — no upload.
The Outlook 20 MB attachment limit
Outlook.com and most Microsoft 365 mailboxes cap attachments at 20 MB, which is stricter than Gmail. The catch that trips people up is the receiver's limit: even if your send succeeds, the recipient's mail server may reject anything over its own threshold, so a message can leave your Outbox and still bounce on delivery. Compressing well under 20 MB gives both ends headroom.
Enterprise tenants sometimes raise or lower the cap, and some route large files to OneDrive automatically as a sharing link. If you'd rather send a genuine attachment than a link the recipient has to authenticate against, shrink the PDF first. fits. reduces the embedded images and leaves text sharp, so the document reads identically on the other side.