Email Attachment Size Checker
Check whether your files fit common email attachment limits before you send them.
Drop your email attachments here
Add one or more files. We calculate everything locally in your browser—nothing is uploaded just to check the size.
Common email attachment size limits
Providers do not all measure large messages the same way. Some limit the original files, while others count encoded attachments or the entire message. Work and school accounts can also use administrator-defined limits.
Gmail
25 MB attachments
Outlook.com
25 MB full email
Yahoo Mail
25 MB attachments
iCloud Mail
20 MB full email
Proton Mail
25 MB encoded attachments
Zoho Mail
20 MB full email
Fastmail
70 MB full email
GMX
50 MB attachments
Why attachments get larger inside an email
Email attachments are commonly encoded with Base64 before they are sent. That conversion adds roughly one third to the original file size before MIME headers and line wrapping are counted.
Example
A 15 MB file can become roughly 20 MB after encoding.
The checker estimates this overhead so a file that looks small enough on disk does not surprise you when the email is sent.
FAQ
Email attachment size questions
The practical details behind limits, encoding, privacy, and what to do when a file is too large to attach.
Does AnyFile upload my files to check their size?
No. The checker reads file-size information locally in your browser. Your files are not uploaded just to calculate whether they fit in an email.
Why is the estimated email size larger than my attachments?
Email attachments are commonly encoded with Base64 before sending. That encoding adds roughly one third to the file size, plus a little more overhead from MIME headers and line wrapping.
Can I check several attachments at once?
Yes. Add all the files you plan to attach and the checker calculates their combined attachment size and estimated encoded email size.
Why can an email still fail even if the checker says it fits?
A recipient's mail server, workplace administrator, security policy, or blocked file type can impose a smaller limit. The checker uses published limits from common consumer email providers as a practical guide.
What should I do if my files are too large for email?
Instead of splitting attachments across messages, upload the file to AnyFile and send a polished share link that recipients can open without creating an account.