What Should The Maximum Size For An Email Attachment Be?

What Should The Maximum Size For An Email Attachment Be?

Office 365 now allows you to define policies limiting the maximum size of email attachments. But just how big is too big?

A recent update to Office 365 allows policies to dictate the maximum size for email email attachments. The previous maximum attachment size was 25MB; now it can be set to anywhere between 1MB and 150MB, and different policies can be applied to different groups of employees.

I’d argue very strongly that even 25MB is too big — at that point, it’s much friendlier to everyone involved to send a link to a file stored in OneDrive/Dropbox/Box/your preferred online storage provider, or point them to an internal network server. What do you think?


  • in a proper business environment sending the actual file(s) rather than a link makes much more sense

    what’s to guarantee that the link is still active in 1 week, 1 month or 1 year? what about mobile devices and other non-desktop clients where access via a browser is a PITA?

    just give me the file please

    • Sounds good in practice but this is a terrible way of doing things. Exchange storage blows way out of proportion and as long as even one copy remains in someone’s mailboxes (including sent items), it can’t be purged. Most system admins will tell you to always store files in network storage, never in email.

      If you’re being sent a file, it’s relevant at the time it was sent. Sure, the link might expire, but odds are if the link did, the file did too. If you need it kept, save it somewhere – most all companies have storage network drives and tons of userspace storage.

      • If you sit at a desk all day then this makes sense. If you are out of the office a lot then that company intranet doesn’t travel with you so you rely on email to get access to a file. It’s not about version control and collaboration, just having access to it when you need it to quickly view or read. Email becomes a quasi file storage in that way.

        • What are you accessing your internet on? Every internet-capable device I’m aware of has local storage you can use.

    • I’d say exactly the opposite. Having multiple versions of files flying around in multiple conversations makes no sense.
      One file, one version. Everyone knows where it is and can collaborate.

    • Disagree. In a proper business environment there should be shared network drives/folders for this purpose. Or managed cloud storage.

      Trying to keep a handle on versioning is damn-near impossible when everyone has their own “personal” copy. Especially now Docs, Sheets and others apps allow multiple simultaneous user access and editing.

  • Generally speaking I try and keep all email attachments under 10MB. Anything larger than that and I’ll try and use a link to to a network share, though there are some exceptions depending on document sensitivity.

    • Under 10 megs is usually best. In practise I generally wouldn’t send anything bigger than 7.5MB.
      Email systems just aren’t reliable and crap out so easily.

  • Man, that picture sure is trippy. The window doesn’t look rectangular to me – the sides look concave.

  • Important distinction to be made: size of attachments vs. total size of email.

    I don’t mind receiving large emails on occasion but as long as the individual attachments are under ~5mb I’m okay with that.

    Reality is that email is often the quickest and easiest way to send a handful of photos/songs /whatever to another person. Having to send 20 emails is not, however.

  • I’m surprised the incredible inefficiency in terms of size (when sending a file via email, due to the email overhead) didn’t get a mention. “Just send me the file” people clearly haven’t got a clue as to how it works. A link to a location where the latest version always lives? Far smarter.

  • Keep in mind that the file size your email system can send/receive isn’t the same as all the other email systems. I always keep attachments under 10MB because someone told me once that was a standard/common threshold. Even though I know I can send larger files, I never know if my recipient can receive larger files.

  • For sending big files, you should definitely try MyAirBridge (www.myairbridge.com). It is great and simple to use service. Totally for free you can send up to 20 GB, with profile even up to 100 GB

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