Why does my 24MB PDF bounce back from a 25MB email limit?

Email servers use MIME (Base64) encoding which adds approximately 33% overhead to binary files. A 24MB PDF becomes roughly 32MB during transmission, causing it to exceed the 25MB limit.

What is the safe PDF size for Outlook and Corporate email?

Outlook limits attachments to 20MB, and many corporate Exchange servers limit them to 10MB. To be safe, compress your PDF to under 8MB using ClonyPDF.

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Fix PDF Attachment Size Limits for Email

Email bounced back due to "Message Too Large"?

Most email servers reject files over 25MB. Optimize your PDF to a safe 15MB size instantly without using ZIP files.

Compress for Email Now ⚡ Compatible with Gmail, Outlook, Yahoo & Exchange

Why your 24MB file fails on a 25MB limit

Many users are confused when a file slightly smaller than the limit still gets rejected. The reason is technical:

⚠️ The 33% Overhead Rule (MIME Encoding)

Email systems convert binary files (PDFs) into text (Base64) to transmit them. This process increases file size by approximately 33%.

Your PDF Size: 20 MB
Actual Email Size: ~26.6 MB (❌ Bounced)

Solution: Compress files to under 18MB to be 100% safe.

Email Provider Limit Cheatsheet

Email Provider	Official Limit	Safe Target Size
Gmail / Yahoo	25 MB	Aim for < 18 MB
Outlook / Hotmail	20 MB	Aim for < 15 MB
Corporate (Exchange)	10 MB (Strict)	Aim for < 7 MB

Common Scenarios

🏢 Corporate Firewalls

Business emails often block large attachments to save server space. Sending a compact 5MB PDF ensures your invoice or contract lands in the inbox, not spam.

📱 Mobile Data Friendly

Recipients opening emails on phones hate downloading huge files. A compressed PDF loads instantly on 4G/5G connections.

Should you Zip or Compress?

Using a ZIP file was the old way. Here is why modern PDF compression is better:

Feature	ClonyPDF Compression	ZIP File
Mobile Access	✅ Opens instantly in email app	❌ Needs to be downloaded & unzipped
Convenience	✅ One click to read	❌ Extra steps for the receiver
Virus Scanners	✅ Trusted format	⚠️ Often blocked by corporate firewalls

Frequently Asked Questions

How do I fix the "Message size exceeds limit" error?

The fastest way is to use our Compress Tool. Upload your file, and our system will remove redundant metadata and optimize images to shrink the size by 40-70%.

Will my PDF look blurry after compression?

Not on screens. We optimize the file specifically for "Screen Viewing," which keeps text sharp and images clear enough for reading, even though the file size drops significantly.

Resize PDF for Email Attachment

🔒 Files are encrypted and deleted automatically