If your iPhone alarm is not going off, start with the alarm itself in the Clock app: is it switched on, is the time and AM/PM right, and is the sound set to something other than None? Those three checks explain most missed alarms. If they look fine, the next suspects are low volume, a dead battery, or a one-time alarm that already used itself up. Below are nine causes, each with the built-in fix first.

Why is my iPhone alarm not going off?

An alarm can fail in two ways. It can fail to fire at all, or it can fire and you cannot hear it. This section covers the first kind. The next sections cover the second.

1. The alarm is off, or the time is wrong

Open Clock and tap Alarms. Look at the toggle on the right of the alarm. If it is grey, the alarm is off. Then read the time closely. A 7:00 PM alarm looks a lot like a 7:00 AM alarm when you set it half asleep. Tap Edit, open the alarm, and confirm the time, the AM/PM, and the days.

One more trap. An alarm with no repeat days rings once and then switches itself off. If you set it last week and expected it to come back, it will not. Add repeat days if you want it every weekday.

2. The phone ran out of battery or was switched off

An iPhone that is off, or out of battery, cannot ring. It sounds obvious, but it is a common reason a morning goes wrong, especially after a long day when the phone was low at bedtime. Plug it in before you sleep, and glance at the battery percentage when you set the alarm.

3. A manual change to the date or time

Apple says that manually changing the time in Settings, for example to trick a game timer, "isn't recommended and can affect alarms" (Apple Support: How to set and change alarms on your iPhone). Set Date & Time to automatic in Settings, General, Date & Time, then check your alarms again.

Is the alarm going off, but you cannot hear it?

This is the second big group, and it is easy to confuse with an alarm that never fired. If you wake up and the alarm toggle is off for a one-time alarm, it did fire. It just did not wake you. Three settings cause most silent alarms.

4. The alarm sound is set to None

Apple notes that if an alarm only vibrates, the sound is likely set to None. Open Clock, tap Alarms, tap Edit, open the alarm, tap Sound, and pick a tone you can hear. This happens after people experiment with sounds, and it is easy to miss because the alarm still shows as active.

5. The volume is too low

Alarm volume follows your Ringtone and Alerts level. Press the volume buttons, or go to Settings, Sounds & Haptics, and drag the slider under Ringtone and Alerts. A low slider is the single most common reason an alarm is technically ringing and still too quiet to wake you. If that is your problem, our guide to an iPhone alarm that is too quiet goes deeper.

Apple also says that, on iPhones with Face ID, Attention Aware features can lower the volume of some alerts when you are looking at the phone (Apple Support: Attention Aware features). Apple does not say whether alarms are affected, so if your alarm seems quieter than your slider, try turning that setting off in Settings, Face ID & Passcode, and test again.

6. Headphones or a speaker are connected

Apple says the alarm plays through the iPhone's speakers as well as wired and wireless headphones. Even so, a pair of earbuds on the nightstand, or a Bluetooth speaker in another room, can make the sound seem to vanish. Disconnect everything you do not need before bed.

Do silent mode and Do Not Disturb stop an alarm?

No. Apple states that Do Not Disturb, the Ring/Silent switch and Silent mode do not affect the alarm sound. That surprises many people, because they silence their phone and then assume the alarm will be silent too. It will not. If you want the longer version, read our guide to alarms on silent, Do Not Disturb and Focus, or Apple's own page on turning a Focus on or off.

7. You are using a Sleep or Wake Up alarm

The Clock app has a Wake Up alarm that follows your sleep schedule, and it has its own sound and volume. If that is the alarm you rely on, open it and check the sound and volume the same way as a regular alarm. If you are a heavy sleeper, adding a regular alarm next to it is a cheap safety net.

8. A third-party app is not ringing

Apps that send their wake-up sound as a notification can be quieted by Silent mode or Focus, and iOS may pause them in the background. Open that app, check its notification and alarm permissions, and run a test. If it still fails, use the built-in Clock alarm for the one that matters.

What if it rang and you slept through it?

9. You turned it off in your sleep, or stopped hearing it

Sometimes the alarm works and the problem is you. You may have tapped Stop or Snooze half asleep and not remembered it. Or the sound has become background noise. When the same tone plays at the same time every morning, the brain learns to filter it out. That is called habituation, and it is why a sound can stop working without anything being broken.

What helps, in order of effort: change the sound every week or two, pick a tone you actually like, and set a second alarm a few minutes later. If you are a deep sleeper, our page for heavy sleepers and the article on how to wake up to your alarm have more ideas. To change the tone on the built-in alarm, see how to change your alarm sound on iPhone.

How do you test the fix?

Do not wait until morning to find out. A two-minute test takes less time than reading this section.

  1. Set an alarm for two minutes from now with the sound you plan to use.
  2. Lock the phone and put it where it will sit overnight.
  3. Switch the ringer to silent and turn on the Focus you use at night.
  4. Wait, and listen from where you sleep. Can you hear it clearly?
  5. If not, raise the Ringtone and Alerts volume and repeat.

Repeat the test after an iOS update or after you restore or change phones, since those are the moments settings are most likely to shift. Nobody can guarantee an alarm, and no app should promise one, so a quick test is the honest safeguard.

Where can AlarmiFex help?

Start with the built-in Clock fixes above. They are free and they work for most people. AlarmiFex is worth a look if your problem is the sound itself: a tone you have stopped hearing, or a morning that starts with a sound you dislike.

AlarmiFex is an alarm app for iPhone and Android with a library of 30+ sounds sorted by mood: Calm, Energetic, Motivational, Classic and Anime. You can preview each one, or import your own clip and trim it. With Wake-up Series you set a time window and several different sounds that play across it, so there is always something fresh for your brain to notice.

On iPhone, AlarmiFex schedules alarms with Apple's AlarmKit. Apple documents that an AlarmKit alarm overrides a device's Focus and silent mode if necessary (Apple Developer: Scheduling an alarm with AlarmKit). So the alarm rings with the app closed and the phone locked, once you allow alarms. It plays at your ringer volume, so keep that turned up, and it cannot ring if the phone is off or the battery is flat. Read more on the rings on silent page, or see how it compares in AlarmiFex vs the iPhone Clock.

The built-in Clock already rings on silent, so AlarmiFex is not a cure for a broken setting. It is for people whose setup is fine and who want a sound they will notice. Using Android? See our guide to an Android alarm not going off.

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