What file size is considered "large" when downloading over a mobile network. For example, if a user comes to check a bunch of PDF's uploaded by an admin, at what time should (s)he be warned about the file size being large and that they will downloading / viewing over the cellular network. Do we have a standard for this?

What could be a possible warning message? From the back of my mind I came up with this:

You are about to view a file that exceeds 10mb size and will be downloaded over the cellular netwrk. Do you wish to continue? Yes/No

Thank you for your response.

2 Answers 2


Any Size

Now that I have your attention, this might be a blunt statement, but it's intrinsically correct. Whenever you make an user download a file, you need to warn about the possible consequences.

As you know, mobile downloads are a beast of its own, and they have rules that don't apply to desktop. They're also affected by:

  • Speed
  • Data Transfer
  • Device's Storage
  • Availability

between other. Your user might cover all of the above, and sometimes they don't. Even the same user on the same device may have different conditions at any given time.

The Productivity Side

Size limits, no matter what device you use, have to account for the specific needs of users. If your admin needs to create a 10Gb document, how are you helping your user by limiting the size to (say) 10Mb? Just imagine telling the user "sorry, we'd love to let you do your work but we can't because we decided a file size and stuff". Again, a blunt simplification, but this is what will happen

Solution: Give control to your users

Simply let your admins or power users upload the files to any file sharing service (Dropbox, Drive, etc) or even create a bucket or download page on your site for download on demand. This way, the end users will decide when and how to download your files. And this time, the files might be of ANY SIZE. Simple and straight to the point.

  • 1
    Good point on the device storage; I forgot about that in my answer! Jun 3, 2016 at 18:21

So if they are not on a WiFi connection, I would have a configurable option to warn if files are greater than ### MB. Some users are likely on an unlimited plan, or are using a phone provided by their company; sounds like your app is an internal app. But in any case, I have a plan that limits my usage to 1 GB/month (and prior plan was like 50 MB/month), so definitely you should warn, and have the level configurable.

In other words, "Large" to me depends on whether I'm on WiFi, or not, and if on cell, how much of my data is left.

  • OP is asking for a size. They already know what they plan to do and that they want to warn, so this doesn't really answer any questions from the post (apart from it possibly being a configurable size). Also, assuming most users will have an unlimited plan is an absolutely terrible assumption to follow. Jun 3, 2016 at 18:19
  • Agreed; I could have worded my answer better, and I said "some" users are "likely" to have an unlimited plan; I wasn't trying to imply most; and yes, that would be a terrible assumption. So yes, my answer could be "make it configurable!" But the app could also be smart enough to see how much space is on the device too, as @devin mentioned. Jun 3, 2016 at 18:27
  • Yeah.. not sure why I said "most", that's my bad. Jun 3, 2016 at 19:29

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