Compress PDF for Outlook

Microsoft documents a 20 MB email size limit for internet email accounts used with Outlook. Exchange business accounts can use a lower default, and an organization’s administrator can configure a different maximum. The receiving company can also reject a message that exceeds its own policy.

That is why the Outlook preset is a practical starting point rather than a universal guarantee. If your workplace error message names a smaller limit, use the Custom option and enter that exact size.

Compressing slightly below the maximum gives the message room for other content and reduces the chance that a receiving server rejects it. If a 20 MB result still fails, try a lower custom target such as 15 MB or the exact number provided by your administrator.

Compression is most effective on PDFs with large photographs or scanned pages. A document made mostly of text may already be efficient, so always rely on the measured compressed size shown after processing.