What email providers actually allow
Most major email services advertise attachment limits in the 20–25MB range, and some allow more between accounts on the same service. But the advertised number is the ceiling for sending — it says nothing about whether the message will be accepted on the other end.
Why the practical limit is much lower
- Encoding overhead. Attachments are MIME-encoded for transport, which typically inflates them by roughly a third. A 20MB file can become ~27MB on the wire and bounce.
- The recipient's server. Corporate and government mail servers frequently cap inbound messages at 10MB or less. Your send succeeds; their server silently rejects or quarantines it.
- Mobile and mailbox reality. Large attachments are slow on cell connections and eat the recipient's storage quota. People notice.
Recommended targets by document type
- Resume / cover letter: under 500KB. Recruiters open these on phones.
- Contracts, invoices, statements: under 1MB.
- Reports with images, brochures: 1–5MB.
- Anything over 5MB: compress it, split it, or send a link.
How to get your PDF email-ready
- Run it through the compressor with the 500KB target (or Auto for light optimization of an already-reasonable file).
- For a long report, consider splitting it and sending only the relevant section.
- Check the result opens cleanly and looks right, then attach.
When to use a link instead of an attachment
If the file genuinely needs to stay large (a print-quality brochure, a 100-page appendix), upload it to a cloud drive and email the link. You bypass every size limit, the recipient downloads only if they want to, and you can update the file after sending. The attachment-vs-link rule of thumb: attachments for documents the recipient must keep (contracts, invoices, resumes), links for everything big or optional.