All of the smartphones I've owned required to hold down the power button for several seconds (ranging from 3 to 8 in some cases) in order to startup from a shutdown state. I've wondered why was such a design decision made? Usability reasons or has it has something to do with the circuitry of the phone? I have never seen another electronic device starting up this way and im curious why they chose to do this on mobile phones.

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    To prevent accidental shut-down or power-up of the device? Considering mobile devices spend a considerable percentage of time in our hands, pockets or bags, having a simple push-button for powering on or off would result in several accidental shut-downs of the device (or accidental power-up of a device meant to be turned off).
    – SNag
    Commented Aug 17, 2014 at 16:54
  • @SNag: Can you think of any reason why holding the power button down for a long time would be required even on phones which flip shut? I've always preferred phones that flip shut to those that hope nothing will trigger erroneous actions while they're in a pocket or bag, every phone I've had, even the ones that flip shut, required an annoyingly long button push to turn on.
    – supercat
    Commented Aug 4, 2015 at 22:37

1 Answer 1


From the electronics perspective, it seems to me if they wanted to implement the "Instant Power On", it was easy to do.

I think the reason for the delay is usability, considering this two aspects:

  • It makes it harder to unintentionally power it on, specially when it is on a pocket

  • Making the act of "Power on" symmetric to the "Power off" act, which makes the user need less knowledge of timings of the device responses.

  • This kind of reminds me of the UX behind why when we hover over web elements on our computer we don't see that popup come up until after seconds later to prevent annoying pop ups all over the place.
    – UXerUIer
    Commented Aug 18, 2014 at 11:55

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