How to compress a PDF for email
Email attachment limits vary by provider, and hitting them is one of the most common reasons people need to compress a PDF at all. Gmail caps attachments at 25MB total (and that 25MB has to cover your message body plus every attachment combined, not just the PDF alone). Outlook and Office 365 are typically capped at 20MB per message, though some enterprise/organizational Outlook setups lower that further — 10MB isn't unusual in corporate environments. Yahoo Mail sits around 25MB as well. If you don't know the recipient's specific provider, aiming well under 20MB is the safest bet.
A quality setting around 60-70% is usually enough to bring a multi-page scanned PDF comfortably under any of these limits while keeping it clearly readable — email attachments rarely need print-level quality since they're almost always viewed on a screen. If you're attaching multiple files in the same email, remember the limit applies to the total, so compress each file with that combined budget in mind.
What's Gmail's attachment size limit?
25MB total per email, combining your message and all attachments together — not 25MB per individual file.
What's Outlook's attachment limit?
20MB is standard for Outlook.com and Office 365, but many corporate/enterprise Outlook configurations set a lower limit (10MB is common), so if you're emailing a work address, aim conservatively.
Why did my email bounce even though my PDF was under the size limit I checked?
A few possibilities: the recipient's provider has a lower limit than yours, their inbox is close to full, or your email's total size (message text plus all attachments together) exceeded the limit even though the PDF alone didn't. Compressing further, or sending fewer attachments per email, usually resolves it.
If a file is still too large after compressing, should I upload it to Google Drive and send a link instead?
It's a reasonable fallback, but a link means the recipient needs a Google account and permission to open it, and the link can expire or get revoked. Compressing further, or splitting a long document into two smaller PDFs, keeps the file as a normal attachment anyone can open without extra steps.
Does zipping a PDF before emailing it help reduce the size?
Barely, if at all — PDFs are already compressed internally, so wrapping one in a ZIP file rarely shrinks it further and sometimes adds a small amount of overhead. Compressing the PDF's actual content (images and embedded fonts) is what meaningfully reduces size, not the container format around it.