Will the alarm still go off if I turn off the phone before?

Example: when I have low battery, I have to go to sleep and wake up at X o'clock, and there is no charger around. Should I turn off the phone?

Note: If it makes any difference my phone is Galaxy S running froyo

  • 2
    Star this issue if you're interested in Google adding the necessary framework for a hardware alarm: code.google.com/p/android/issues/detail?id=1942 However, due to the open nature of Android, in the end, it is up to manufacturers to include the necessary hardware for powered-off alarm, and it is impossible for Google to force all manufacturers to do so. – Lie Ryan Dec 30 '10 at 4:54
  • Useless functionality from android – Rasmi Ranjan Nayak Aug 2 '14 at 19:16
  • Due to this inconvenience from Android, I've bought a small Alarm Clock on ebay. – T.Todua Jul 4 '15 at 17:06
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    Actually, it works on OnePlus One (forums.oneplus.net/threads/power-off-alarm.300539) The phone will start itself up, to trigger the alarm! (Probably more brands have this, but experienced it on my OPO.) – Paul Feb 16 '16 at 12:50
  • Cyanogenmod has this feature. Its installed on OnePlus One. You can install it on Galaxy S though. – Ondrej Bozek May 12 '16 at 6:36

No, if the phone is off, it can't do anything. If it's in sleep mode where the screen is off and it's not in use then the alarm will still function as will other types of notifications. I have never tried this specifically on a Galaxy S but I am fairly confident this is a universal rule.

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    really? on old phones (like nokias) the alarm still rings when the phone is turned off. that's disappointing in android – Louis Rhys Dec 30 '10 at 3:17
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    I'll confirm this as a Galaxy S owner. When the phone is off, it's actually off. Not a powered-down mode. – Matthew Read Dec 30 '10 at 3:19
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    I used to have an N95 and I never knew that. I am pretty sure, but there's only one way to be sure, try it out. Set the alarm for 5 minutes from now and then turn the phone off. – Matt Dec 30 '10 at 3:20
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    VERY disappointing in deed ! The old nokia did it - I was expecting the smarter android (Galaxy S GTI9000) to do even better... but hence - Nothing! – hanani Jan 19 '11 at 20:51
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    In the motorola razr d3 it's works when the phone is off :) – Enrique San Martín Jan 22 '14 at 20:12

Unfortunately, it doesn't work when phone is powered off as some have already suggested.

My suggestion: put it into Airplane Mode - this way, the phone almost consumes zero energy (due to not having any network connection and so on), and you have a good chance that the battery will last until the morning where the alarm shall go off!

  • But I like to have a soft reset of all the phone ram and components and co over night by turning it off. My Lenovo K6 automatically turned on when the alarm time came, why don't the more expensive phones support it... – Xerus Oct 4 '18 at 4:58


Tested it. It didn't go off when the phone was off.


I have a OnePlus2 and I got a new phone to replace it. I turned the OnePlus2 off and left it unplugged overnight but didn't disable the alarm. It automatically powered on and rung the alarm in the morning twice for me so far.

So, depending on your phone model, this does seem to be a thing these days.

  • Can somebody explain how this works? – Athira May 30 at 10:06
  • It looks like for OnePlus it’s an added feature: forums.oneplus.com/threads/power-off-alarm.300539 . The closest thing in Android API I can see is RTC_WAKEUP, but that only works when the device is on (the wakeup refers to the device being in sleep mode such as a locked screen). So, the way it probably works on OxygenOS is that the proprietary alarm app stores its state in a file which OxygenOS reads when shutting down and sets a power wake thing in hardware somewhere. – binki May 30 at 14:43

protected by ale Apr 5 '11 at 19:46

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