Windows and Mac both let you change the system time in Settings, though the steps differ slightly between them

Your PC's internal clock controls when files are saved, when scheduled tasks run, and what time appears in the corner of your screen. If your clock is wrong, you can fix it yourself in a few clicks—you do not need to restart your computer or call anyone. The process takes less than a minute on either Windows or Mac.

Most of the time, your PC sets the time automatically by connecting to a time server on the internet. If automatic time is turned on and your clock is still wrong, the problem is usually that your internet connection is unstable or your time zone setting is incorrect. Turning off automatic time and setting it manually is a temporary fix; the real solution is to check your internet connection and time zone first.

Key Takeaways

  • On Windows 11, open Settings, go to Time & Language, then Date & Time, and toggle off "Set time automatically" to change the time manually.
  • On Mac, open System Settings, click General, then Date & Time, and uncheck "Set date and time automatically" before entering a new time.
  • If your clock keeps drifting wrong even after you set it, check that automatic time is turned on and that your internet connection is stable.
  • Changing your time zone is a separate step from changing the time itself, and getting the time zone wrong is a common reason clocks appear incorrect.

How to change the time on Windows 11

Open the Start menu and type "Settings" into the search box, then click the Settings app. On the left side, click Time & Language. Then click Date & Time.

You will see a toggle labeled Set time automatically. Click it to turn it off. Once it is off, two new fields will appear: one for the date and one for the time. Click the time field and enter the correct time using the hour and minute boxes. Click outside the field to save your change.

If you also need to change the time zone, scroll down on the same page and find Time zone. Click the dropdown and select your time zone from the list. Your PC will use this zone to calculate what time it should display.

How to change the time on Mac

Click the Apple menu in the top-left corner and select System Settings. On the left sidebar, click General. Then click Date & Time.

You will see a checkbox labeled Set date and time automatically. Uncheck it. A new window will open with fields for the date and time. Click the time field and type the correct time in the format shown (usually HH:MM AM/PM). Press Enter to save.

To change your time zone on Mac, stay on the same Date & Time page and look for the Time zone dropdown. Click it and search for your city or region, then select it from the list.

Why your clock might be wrong even after you set it

If you set the time manually and it drifts wrong again within hours or days, automatic time is probably still running in the background. Go back to the time settings and make sure the "Set time automatically" toggle is actually off—sometimes it turns itself back on after a restart or update.

If automatic time is off and the clock is still drifting, your PC's internal battery (called the CMOS battery on desktop computers) may be failing. This battery keeps the clock running when the PC is unplugged. A failing battery will cause the time to reset or drift every time you restart. If this is happening, the PC will need a hardware repair, and you should contact the manufacturer or a local repair shop.

If automatic time is on and the clock is still wrong, your internet connection may be unstable or your time zone may be set incorrectly. Check that you are connected to the internet and that your time zone matches your actual location. If you recently moved or traveled, the time zone setting may not have updated automatically.

The difference between time and time zone

Your time is the actual hour and minute (for example, 3:45 PM). Your time zone is the region you are in, which determines how many hours ahead or behind you are from a reference point called UTC (Coordinated Universal Time). If you set the time to 3:45 PM but your time zone is set to a zone that is 5 hours behind your actual location, your clock will show the wrong time even though you entered it correctly.

When you change your time zone, your PC automatically adjusts the displayed time to match. For example, if you move from Eastern Time to Pacific Time (3 hours behind), your PC will subtract 3 hours from the displayed time. You do not need to manually re-enter the time when you change zones—the PC does the math for you.

When to turn off automatic time and when to leave it on

Leave automatic time on in almost all cases. It keeps your clock accurate without any work from you, and it updates automatically when daylight saving time begins and ends. The only reason to turn it off is if you are testing something, troubleshooting a problem, or temporarily need a different time for a specific reason.

If you turn off automatic time, remember to turn it back on when you are done. A PC with automatic time off will slowly drift out of sync with the real time, which can cause problems with file timestamps, scheduled backups, and security certificates. If you notice your clock is wrong weeks later, the first thing to check is whether automatic time got turned off accidentally.

Frequently Asked Questions

Do I need to restart my PC after changing the time?

No. The time change takes effect when ready. You do not need to restart, log out, or close any programs. If you are running a scheduled task that depends on the time, it will use the new time right away.

What if the time zone dropdown does not show my city?

Search for the nearest major city in your time zone, or search by the time zone name itself (for example, "Eastern Standard Time" or "Pacific Standard Time"). Your PC does not need to know your exact city—it only needs to know which time zone offset you are in.

Can I set the time to something that is not the real time?

Yes, but do not do it unless you have a specific reason. Setting a false time will cause file timestamps to be wrong, scheduled tasks to run at the wrong moment, and security certificates to appear expired. If you need to test something with a different time, change it back as soon as you are done.

Why does my PC keep changing the time back after I set it?

Automatic time is probably still on. Return to Time & Language > Date & Time and confirm that "Set time automatically" is toggled off. If it is off and the time still changes, your internet connection may be overriding your manual setting, or your CMOS battery may be failing.