Change the time format in Settings

Open Settings on your iPhone and tap General. Scroll down and tap Date & Time. You will see a toggle labeled 24-Hour Time. Turn it on to display time in 24-hour format (13:00 instead of 1:00 PM), or turn it off to use 12-hour format with AM and PM.

The change takes effect when ready across your iPhone — the lock screen, home screen, Control Center, and all apps that display the system time will update to match your choice. Some third-party apps may not follow this setting and will keep their own format, but Apple's built-in clock and time displays will respect your preference.

Key Takeaways

  • The 24-Hour Time toggle is in Settings > General > Date & Time, and switching it changes the time format across your entire iPhone.
  • Turning on 24-Hour Time displays hours from 00 to 23 instead of 1 to 12 with AM or PM labels.
  • The change applies to your lock screen, home screen, Control Center, and Apple's built-in apps when ready.
  • Third-party apps may not follow this setting and may continue to show 12-hour time regardless of your choice.

Where the time format shows up on your iPhone

Once you change the setting, the new format appears in several places. Your lock screen will show the time in your chosen format when you wake the phone. The home screen clock widget, if you have one, will update. The Control Center — the panel you pull down from the top right — will display the time in your selected format.

The Clock app itself, including the timer and stopwatch, will also reflect your choice. Notifications and alerts that include a timestamp will use the format you selected. However, if you use apps like WhatsApp, Gmail, or other third-party messaging and email services, those apps may have their own time format settings that override the system setting.

Why you might want to switch formats

Some people prefer 24-hour time because it removes ambiguity — there is no confusion between morning and afternoon, and it is the standard in military, aviation, healthcare, and many international contexts. If you travel frequently or work in a field that uses 24-hour time, switching your phone to match can reduce mental switching between formats.

Others find 12-hour time more natural because it is what they grew up with and what most everyday clocks display. There is no performance benefit or drawback to either choice — it is purely about what you find easier to read and remember.

Changing the format for individual apps

If you want a different time format in a specific app, check that app's own settings. Open the app, look for a Settings or Preferences menu (often found by tapping your profile icon or a gear icon), and search for time or date format options. Not all apps offer this choice, but many do.

For example, some calendar apps let you choose whether to show 12-hour or 24-hour time independently of your system setting. Email and messaging apps vary — some follow your system setting automatically, while others have their own toggle. If an app does not offer a time format option, it will either follow your system setting or use its default, and you cannot change it within that app.

Reverting to 12-hour time

If you switch to 24-hour time and decide you prefer 12-hour format, the process is the same. Go to Settings > General > Date & Time and toggle 24-Hour Time off. Your iPhone will when ready revert to showing AM and PM labels and hours numbered 1 through 12.

You can switch back and forth as many times as you want with no side effects. Your alarms, reminders, and calendar events will not be affected by the change — only how the time is displayed to you.

Troubleshooting if the time format does not change

If you toggle the 24-Hour Time setting and the display does not change, restart your iPhone. Press and hold the side button and either volume button until the power-off slider appears, then drag it to turn off the phone. Wait a few seconds, then press and hold the side button again until the Apple logo appears.

If the time format still does not update after a restart, check whether you have an app open that displays its own clock. Some lock screen widgets and always-on displays may cache the time format and need to be refreshed. Swipe away the widget or lock your phone and unlock it again. If a specific app is not updating, that app may not support the system time format setting, and you may need to check its own preferences.

Frequently Asked Questions

Does changing the time format affect my alarms or reminders?

No. Your alarms and reminders will continue to work exactly as they did before. The change only affects how the time is displayed to you — the underlying time data does not change. If you set an alarm for 6:30 AM, it will still go off at 6:30 AM whether your display shows "06:30" or "6:30 AM".

Will changing the time format on my iPhone change it on my iPad or Mac?

No. Each device has its own Date & Time settings. If you want the same time format across all your Apple devices, you will need to change the setting on each one separately. Go to Settings > General > Date & Time on iPad, or System Settings > General > Date & Time on Mac.

Can I set different time formats for different times of day?

No. The 24-Hour Time toggle is all-or-nothing — you cannot schedule it to switch automatically or set it to show one format in the morning and another in the evening. Your choice applies all day. If you need different formats at different times, you would need to manually toggle the setting.

Why does my app still show 12-hour time even though I turned on 24-hour time?

That app does not follow your system time format setting. Some third-party apps have their own time format preference that overrides the iPhone setting. Check the app's own settings menu for a time or date format option. If the app does not offer one, you cannot change how it displays time.