Open System Settings and find the date and time controls

The fastest way to change your Mac's time is through System Settings. Click the Apple menu in the top-left corner, then select System Settings. In the sidebar, scroll down and click General, then select Date & Time.

You will see your current time zone and the option to set the time manually. If your Mac is set to update automatically (the default), you will need to turn that off first before you can change the time yourself.

Key Takeaways

  • Go to Apple menu > System Settings > General > Date & Time to reach the time controls on any Mac.
  • Turn off "Set date and time automatically" if it is on, otherwise the system will override any manual changes you make.
  • You can change the time zone, the date, or both, depending on what your Mac needs.
  • If your Mac keeps resetting to the wrong time, the battery that powers the internal clock may be failing and needs replacement.

Turn off automatic time updates

By default, macOS sets the time and date automatically using Apple's time servers. If you want to change the time manually, you must first uncheck the box next to Set date and time automatically. Once you do, the time and date fields will become editable.

This setting exists because most people want their Mac to stay accurate without thinking about it. Turning it off means your Mac will keep whatever time you set, even if it drifts from the actual time. You can turn automatic updates back on at any time by checking the box again.

Change the time zone without changing the time

If you only need to change your time zone—for example, because you moved or are traveling—you can do that without touching the actual time. In the Date & Time settings, click the dropdown next to Time zone and select your location from the list. Your Mac will automatically adjust the displayed time to match.

This is the most common reason to visit these settings. If you are in New York and your Mac thinks you are in Los Angeles, the time will be three hours off. Changing the zone fixes it when ready without you having to set the clock manually.

Set the time and date manually

After you turn off automatic updates, click the time or date field to edit it. A small calendar and clock will appear. Use the arrows or type directly into the fields to set the correct month, day, year, hour, and minute. Click outside the fields or press Enter when you are done.

The time format depends on your language and region settings. If you see a 24-hour clock and prefer 12-hour format (or vice versa), you can change that in System Settings under General > Language & Region, in the Time format section.

What to do if your Mac keeps changing the time back

If you set the time manually and it keeps resetting to a different time, automatic updates may have turned back on, or your Mac may be connecting to a time server. Check the Date & Time settings again and make sure Set date and time automatically is still off.

If it is off and the time still changes, the problem is usually the PRAM battery (or NVRAM battery on older Macs), a small internal battery that keeps the clock running when your Mac is shut down. When this battery fails, the Mac loses track of time and resets to a default when it restarts. A repair technician can replace it, but this is a hardware issue that software changes cannot fix.

Sync your Mac's time with your iPhone or other devices

If you want your Mac to match the time on your iPhone or iPad, the easiest approach is to turn automatic time updates back on for both devices. They will all sync to Apple's time servers and stay in agreement. This is more reliable than trying to match them manually.

If you need them to match a specific custom time (for example, for testing or video production), set that time on one device first, then manually set the others to match. Keep automatic updates off on all of them while you are working, then turn it back on when you are done.

Frequently Asked Questions

Can I change the time on my Mac without going to System Settings?

You can click the time display in the menu bar at the top of the screen and select "Date & Time Preferences," which opens the same settings window. This is slightly faster than going through the Apple menu, but it takes you to the same place.

What happens if I set my Mac's time to the future or past?

Your Mac will use whatever time you set. This can cause problems with file timestamps, email, and some applications that depend on accurate time. Websites may also refuse to load if your Mac's time is too far off. Set it back to the correct time as soon as you are done testing.

Why does my Mac keep asking me to update the time zone?

If you travel frequently, macOS may detect your location and suggest a new time zone. You can ignore these notifications or turn off location services for date and time in System Settings under Privacy & Security > Location Services. This prevents the automatic suggestions but keeps the rest of location services on.

Does changing the time on my Mac affect my backups?

Time Machine backups will use whatever time your Mac is set to when the backup runs. If your Mac's time is wrong, the backup timestamps will be wrong too. This usually does not cause problems, but it can make it harder to find the backup you need if you are looking by date.