How to Compress a PDF for Email

The email bounces back, or worse, it sends and just never arrives, no error, no explanation. Most attachment size limits are silent until you hit them, and by then you've already lost time.

Gmail and Outlook.com both cap attachments at 25MB. A lot of corporate Exchange servers set the bar lower, sometimes 10-20MB, without telling you until the message fails.

Get under the limit

• Run the file through Compress PDF on Medium first, that's usually enough for a scanned contract or a report with a handful of photos.
• If it's still too large, drop to Low, the text stays fully readable even though photographs lose some detail.
• For anything still over the limit after that, the file is probably mostly high-resolution scans rather than compressible photos, splitting it into two emails is often faster than fighting for a smaller size.

A habit worth building

If you regularly send the same kind of document (invoices, signed forms, reports), compress before attaching becomes a habit worth having rather than a fire you put out each time a message bounces.