It may be silly to assume that your alarm will still work if your phone is off, but a lot of phones actually used to work this way. In fact, some Android devices still do.
Will My Alarm Work If My Phone Is Turned Off?
Some Android phones offer a feature that automatically turns your phone back on at a certain time if you shut it down before going to bed. The manufacturers that offer this feature vary greatly, and it appears to be sort of a dying feature at this point. If your phone has it, you can find it in Settings > Scheduled Power On & Off. It’s a pretty nice tool if you like to shut your phone off at night.
Of course, most people don’t bother shutting their phones off at night before going to bed like back in the feature phone days. Most phones are lucky to get a single reboot once a week. That said, if you forget to plug in your charger (or your power goes off overnight), your alarm can be a bit of concern.
So while your particular model of phone may have a feature that automatically turns the phone back on before the next alarm, it won’t help if you forget to charge your phone and it dies overnight. You’ll be left to wake up on your own, which is pretty scary for most of us.
It’s also worth pointing out that Android’s “silent” settings can be confusing—while you can turn your ringer all the way off, that only silences calls and (maybe) messages. For true “silent” mode, you’ll need to use Do Not Disturb, which can sometimes be confusing on Android.
Will My Alarm Go Off if My Phone is In Do Not Disturb Mode?
Android offers pretty granular settings when it comes to Do Not Disturb—you can choose whether or not to allow alarms through on most phones.
To check these settings, pull down the notification shade, and then find the “Do Not Disturb” icon (you may have to pull the shade down twice on some phones). Long-press that icon to go straight to its settings.
From there, you can set custom exceptions—like allowing alarms to bypass Do Not Disturb. The verbiage and exact menus may be slightly different depending on your phone’s manufacturer and version of Android, but if this rule is present, it will be somewhere in the Do Not Disturb menu.
What About Other Reminders and Timers?
Timers and reminders (calendar events and the like) don’t fall into the same category as alarms on Android. You can specifically choose to allow or disallow reminders or events to bypass Do Not Disturb settings if you’d like.
This way, you can choose to silence calendar events or reminders while Do Not Disturb is on, but still allow alarms—or any mix of the three.