Will my alarm go off if my phone is on silent?

Apple's Clock alarm will, and Apple says so directly: switching on Silent mode does not stop the alarm sounding. A third-party alarm that relies on notifications will not, because the silent switch mutes notifications.

Does the alarm go off on Do Not Disturb?

Yes. Do Not Disturb and the other Focus modes silence notifications, not alarms. The same split applies: a real alarm rings, an alarm app built on notifications does not.

What about Sleep Focus?

Sleep Focus is built around your sleep schedule and its wake-up alarm is a real alarm, so it sounds. It also dims your Lock Screen, which surprises people, but it does not mute the alarm.

How do I know if an app sets a real alarm?

Ask what happens on silent. If the honest answer is a notification, silent and Focus will mute it. On iOS 26 and up, look for AlarmKit specifically, which is the only way an app gets the same treatment as Apple's alarm.

Does your alarm go off on silent or Do Not Disturb?

For Apple's own alarm the answer is simply yes, and Apple documents it. The catch is that this is not true for most alarm apps, which is probably why you are asking.

Apple's alarm: yes, both

Apple's support documentation is unambiguous: if you use the Ring/Silent switch or Action button to turn on Silent mode, or turn on Do Not Disturb, the alarm still sounds. Clock alarms play through the built-in speaker even when Silent mode is on.

Do Not Disturb is a Focus, so the same holds for the other Focus modes: they silence notifications, not alarms. You do not need to leave your ringer on overnight to be woken up.

So why do people sleep through it anyway?

Because two different things are called an alarm. A system alarm is allowed past silent and Focus. A notification is not, and most third-party alarm apps schedule exactly that.

If your experience is that the alarm did not sound on silent, you almost certainly were not using a system alarm. It is not a bug in your phone and no amount of toggling Do Not Disturb will fix it.

The volume is still yours to get wrong

Being allowed to play is not the same as being loud. The alarm plays at your ringer volume, which is separate from media volume, and the side buttons can quietly lower it when no media is playing. If your alarm sounds but barely, that is a volume question, not a silent-mode question.

What AlarmKit changed

Since iOS 26 an app can set a real system alarm through AlarmKit instead of faking one with a notification. That is the same layer Apple's Clock uses, so it gets the same treatment: through silent, through Focus, ringing until you stop it.

NanoTimer uses it. On iOS versions below 26 there is no way to do this, so it falls back to a notification and we tell you that instead of quietly hoping you do not notice.

A real alarm, not a notification

NanoTimer sets an AlarmKit alarm (iOS 26+): through silent, through Focus, ringing until you stop it. Free, no ads, no subscription.

Open on your phoneOpens the right tab in NanoTimer on your iPhone.

Download on theApp StoreLink coming soon

Frequently asked questions

Will my alarm go off if my phone is on silent?: Apple's Clock alarm will, and Apple says so directly: switching on Silent mode does not stop the alarm sounding. A third-party alarm that relies on notifications will not, because the silent switch mutes notifications.
Does the alarm go off on Do Not Disturb?: Yes. Do Not Disturb and the other Focus modes silence notifications, not alarms. The same split applies: a real alarm rings, an alarm app built on notifications does not.
What about Sleep Focus?: Sleep Focus is built around your sleep schedule and its wake-up alarm is a real alarm, so it sounds. It also dims your Lock Screen, which surprises people, but it does not mute the alarm.
How do I know if an app sets a real alarm?: Ask what happens on silent. If the honest answer is a notification, silent and Focus will mute it. On iOS 26 and up, look for AlarmKit specifically, which is the only way an app gets the same treatment as Apple's alarm.