Regarding my previous question on user activity, how long is the ideal amount of time to allow the computer to sit idly before considering the user to be away?

In my current application of this method, it is far better to receive a false negative ("user is not active"), than a false positive ("user is active"), so therefore a relatively shorter time will probably be better for my specific instance.

However, I'd like to see some input and justification for any definition of sufficient, concerning idle time with regards to general use.

  • What sort of device is this? From your previous question it sounds like a desktop PC?
    – Zelda
    Commented Dec 28, 2011 at 16:18
  • Yes, in my instance it's a computer running Mac OS X. Commented Dec 28, 2011 at 17:29

3 Answers 3


Screensavers have been almost since the beginning of computing a reference for "user is away".

Typically a screensaver would trigger at 3 minutes by default, but the amount of idle time before it triggers is adjustable by the user.

  • 1
    It appears as though, at least in XP, Microsoft's screensaver default was 10 minutes: support.microsoft.com/kb/314493. I cannot find anything more recent yet.
    – Karen
    Commented Dec 28, 2011 at 15:31
  • 3
    3 minutes seems pretty short for a desktop, about right for a laptop on battery. FWIW I beleive the iPad screen turns off after 5 minutes, most smartphones I've had default to 1 minute. Use-case for the device + battery concerns usually shape the time.
    – Zelda
    Commented Dec 28, 2011 at 15:33

Banking websites typically log users out automatically after 10 minutes of idle (no input) time. 10 minutes allows for trips to the restroom/water cooler, grabbing more coffee, or a quick chat with a coworker.

However, for mobile devices, I think the standard is a bit different. If my screen has been off for 1 or more minutes, chances are my phone can be considered idle. Since phones are generally not useful with their screen off (exception being music playing), it's a good measure of if the user is actually using the device vs passively listening to it. If the choice is an idle computer or a screen-off mobile device with music playing, though, I'd alert the mobile device.

  • No input, or no POST? ;) (My bank uses the latter, I wish they were more sophisticated and used the former…)
    – msanford
    Commented Dec 28, 2011 at 17:38
  • +1 for some real-word examples, but ideally I want the most accurate data possible. If a user needs to grab some coffee, I want the data to go with him (via smartphone). Commented Dec 29, 2011 at 3:15
  • My own anecdata here: if I'm only going to be gone a few minutes, I won't take my phone unless I'm expecting a call or alert. At least at work, longer trips away from my desk increase the chances that I'll bring my phone with me.
    – Karen
    Commented Dec 29, 2011 at 13:24

It depends on your app and how it's used. If you have a decent workflow model, you should be able to ballpark the time a user needs to spend away from the app (i.e. in another app or away from keyboard) - some might need as little as 1 minute and others as much as 5-10 minutes.

If you can, do alpha/beta testing and measure idle times there so that the production version has a sensible default.

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