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Email Attachment Sizes

Email is used each day to send files to people. Using email to send files is fine for sending some pictures to Grandma or even a Word doc to a work colleague but when it comes to sending something more though you can end up having issues. The main issue with sending attachments over email is the size of the file.

I emailed someone an attachment and I got a message saying it was too big. What size attachment can I send?

Email providers limit the size of attachments that can be sent, and it will vary. If your provider allows you to send a 20 MB size attachment, and the person you are sending it to is only allowed to receive emails that are 10 MB in size, then you are limited to the 10 MB in size. It doesn't take much these days to use up 10 MB worth of attachments. A couple of large high quality photos or a short video can easily be over 10 MB in size.

If you can send or receive a 20 MB email, you also have to worry about the size of the mailbox. A couple of large emails can quickly fill up someone's available mailbox space causing them to start bouncing emails because their mailbox is full.

Why are there size limitations on email attachments?
Email was never really designed for sharing large files. When someone sends an email with a large attachment, it is usually scanned for viruses by the server that receives it. Scanning a 10 or 20 MB file takes some time. This is not too bad if it's just one email, but when you start getting hundreds of thousands or even millions of emails a day, and you add large attachments to a lot of them, well you can expect long delays in receiving your email.

Also trying to download a large attachment into Outlook or something similar can cause timeouts or at least make you wait quite a while to receive any emails. Your own antivirus software will sometimes have issues with large attachments as it tries to scan the email and the file for viruses.

Does it matter what type of file I send?
The type of file you send over email can also be problematic. With so many viruses and other malware out there these days, many types of files are blocked or restricted over email. If your email program itself doesn't block it, your antivirus software might, or your IT department and/or email provider may also.

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