Quick answer
The short version
Compress the PDF with the balanced setting, then keep the attachment comfortably below the email provider limit because message encoding adds overhead. Open the downloaded copy before sending, confirm that links and small text still work, and use an approved secure sharing method instead of extreme compression when the document remains too large.
Compress PDFStep-by-step
A reliable workflow
- 01
Find the sender and recipient attachment limits and choose a lower working target.
- 02
Use balanced PDF compression and download the optimised copy.
- 03
Open the copy and inspect text, images, links and the page count.
- 04
Rename it clearly without adding confidential details to the filename.
- 05
Attach it to a test draft and confirm the message remains below the service limit.
Allow for email encoding overhead
Email systems usually encode binary attachments for transport, which makes the complete message larger than the file displayed on disk. Signatures, inline images and earlier messages in a reply chain also contribute to the message size.
Do not aim exactly at the published maximum. A comfortable margin reduces the chance that a recipient server rejects the message after it leaves your outbox.
Choose compression or sharing based on sensitivity
For ordinary documents, balanced compression is often enough. For confidential, regulated or very large files, use a sharing method approved by your organisation rather than repeatedly degrading the PDF or sending it through an unsuitable channel.
- Confirm the recipient can access any shared link before relying on it.
- Avoid public links for private documents unless access controls are configured.
- Send passwords through a separate approved channel when policy requires it.
Before you continue
Limitations
- Email providers and recipient gateways use different limits.
- Compression does not encrypt an attachment or make email a secure delivery channel.
- Interactive forms, portfolios and embedded attachments may change during optimisation.
Questions
Troubleshooting and common questions
Why is my email larger than the PDF?
Binary attachments are encoded for email transport, and the message body, signatures and inline images add more data.
Can I split the PDF across two emails?
Only if the recipient expects separate parts. A controlled sharing link is usually easier to track than a multi-message document.