Switch between 12-hour and 24-hour time on your iPhone

You can change whether your iPhone shows the time as 12-hour (with AM and PM) or 24-hour (military time) in the Settings app. The change affects your lock screen, home screen, Control Center, and most built-in apps. The setting is in one place, and it takes about 30 seconds to flip.

Open Settings, tap General, then tap Date & Time. Toggle the switch next to 24-Hour Time on or off. When the toggle is green and switched right, your iPhone displays 24-hour time. When it is off, you see 12-hour time with AM and PM labels.

Key Takeaways

  • The 24-hour time toggle is in Settings > General > Date & Time, and the change takes effect when ready across your phone.
  • Turning on 24-hour time removes AM and PM labels and shows hours from 00 to 23 instead of 1 to 12.
  • Some third-party apps may not respect this setting and will continue showing 12-hour time regardless of your choice.
  • The setting syncs across your iPhone, iPad, and Mac if you use the same Apple ID and have iCloud sync turned on.

What changes when you turn on 24-hour time

When you enable 24-hour time, your iPhone stops showing AM and PM. Instead, midnight is 00:00, noon is 12:00, and 11 p.m. becomes 23:00. The lock screen clock, the time in your status bar, and the time shown in Calendar, Mail, and Messages all switch to this format.

The Alarm app, Clock app, and world clock all display in 24-hour format too. However, some third-party apps—particularly older ones or those designed primarily for the US market—may ignore this system setting and continue showing 12-hour time. There is no way to force those apps to change; you would need to contact the app maker or look for an in-app setting.

Step-by-step: How to find and toggle the setting

Start by opening the Settings app on your home screen. Tap General, which is usually the second option in the list. Scroll down and tap Date & Time.

You will see several options on this screen: Set Automatically (which you can leave on), Time Zone, and 24-Hour Time. The 24-Hour Time toggle is near the bottom. Tap the toggle to turn it on (it will turn green) or off (it will turn gray). Your iPhone applies the change when ready—you do not need to restart or confirm anything.

What happens if you turn off Set Automatically

Normally, your iPhone sets the time and time zone automatically based on your location and your carrier's network. If you turn off Set Automatically, you can manually enter the time and time zone yourself. This is rarely necessary unless you are troubleshooting a time display problem or testing how your phone behaves with a specific time.

If you do turn off automatic time setting, your iPhone will not update when you travel to a different time zone. You would have to change the time zone manually each time. For most people, leaving Set Automatically on is the right choice.

How the setting syncs across your devices

If you own multiple Apple devices—an iPhone, iPad, and Mac—and you sign in with the same Apple ID, your 24-hour time preference syncs across them automatically through iCloud. Change the setting on your iPhone, and your iPad and Mac will update within a few minutes, as long as they are connected to Wi-Fi or cellular data.

This sync happens only if you have enabled iCloud sync for Date & Time settings. If you have turned off iCloud sync or use different Apple IDs on different devices, each device keeps its own separate setting. You would need to change the 24-hour time toggle on each device individually.

Why your clock might still show 12-hour time after changing the setting

If you toggled 24-hour time on but your lock screen still shows AM and PM, restart your iPhone. Close all apps, hold down the power button until you see the shutdown slider, slide to power off, wait a few seconds, then press the power button again to turn it back on. This clears any display glitches that prevent the setting from taking effect.

If the setting still does not work after a restart, go back to Settings > General > Date & Time and confirm the toggle is actually on (green and switched to the right). If it is on but your phone is still showing 12-hour time, the issue may be with a specific app rather than your system setting. Check whether the app has its own time format setting in its preferences.

Frequently Asked Questions

Does changing to 24-hour time affect alarms or reminders?

No. Your alarms and reminders work the same way regardless of which time format you display. The change only affects how the time is shown on screen. If you set an alarm for 6 p.m., it will go off at the same moment whether your phone shows 18:00 or 6:00 PM.

Can I set 24-hour time for just the lock screen and not the rest of my phone?

No. The 24-hour time setting is system-wide. When you turn it on, it changes the time display everywhere on your iPhone at once. You cannot explore it to only the lock screen or only certain apps.

What if an app does not respect the 24-hour time setting?

Some apps, especially older ones, do not follow your system time format setting. Check the app's own settings or preferences menu—many have a separate time format option. If the app has no such option, contact the app maker to request the feature, or consider using a different app that does support 24-hour time.

Will turning on 24-hour time drain my battery?

No. Changing the time display format has no effect on battery life. It is purely a visual change and does not alter how your iPhone processes or uses power.