How to change your computer's clock

The fastest way to change your computer's clock depends on whether you use Windows or Mac. On Windows, right-click the time in the bottom-right corner of your screen and select "Adjust date and time." On Mac, click the Apple menu in the top-left, go to System Settings, then Clock, and adjust from there. Both systems let you change the time manually, though most computers sync automatically with internet time servers and correct themselves without your input.

If your clock is wrong, the cause is usually a dead battery in your computer's internal clock chip, a disconnected internet connection, or a time zone setting that drifted. Fixing it takes less than a minute once you know where to look.

Key Takeaways

  • Windows users right-click the system clock in the taskbar and select "Adjust date and time" to change the time manually.
  • Mac users open System Settings, navigate to General, then Clock, and adjust the date and time from there.
  • Most computers automatically sync with internet time servers, so manual changes are rarely necessary unless your internet is down.
  • If your clock keeps resetting or showing the wrong time after restart, your computer's internal battery may be failing and needs replacement by a technician.

Changing the time on Windows 10 and Windows 11

Right-click the time display in the bottom-right corner of your taskbar. A menu will appear with several options. Select "Adjust date and time" to open the date and time settings window.

In the settings window, you will see a toggle for "Set time automatically." If this toggle is on (blue), your computer is syncing with an internet time server and will correct itself. Turn it off if you want to set the time manually. Once it is off, a button labeled "Change" will appear below it. Click "Change," enter the correct date and time, and select "OK." Your computer will update when ready.

If you only need to change the time zone, scroll down in the same settings window and look for "Time zone." Click the dropdown and select your zone from the list. This is useful if you travel or if your computer is set to the wrong region.

Changing the time on Mac

Click the Apple menu in the top-left corner of your screen and select "System Settings" (or "System Preferences" on older macOS versions). In the sidebar, find and click "General," then look for "Date & Time" in the main panel.

You will see options to set the date and time. If "Set date and time automatically" is checked, your Mac is syncing with an internet time server. Uncheck this box to set the time manually. Once unchecked, you can click on the date and time fields and type in the correct values. Your Mac will save the change when ready.

To change your time zone, look for the "Time zone" dropdown in the same Date & Time section. Select your zone from the list. If you are unsure which zone you are in, you can search by city name.

Why your computer's clock might be wrong

The most common reason a computer's clock drifts is a dead or dying CMOS battery—a small coin-shaped battery inside your computer that keeps the internal clock running even when the machine is powered off. When this battery fails, the clock resets to a default date and time every time you restart. If your clock is consistently wrong after you shut down and turn back on, this is the likely culprit.

A second reason is that your computer is not connected to the internet. Most modern computers sync their clocks with Network Time Protocol (NTP) servers, which are internet-based timekeeping services. If your internet connection drops, your computer cannot update its clock and may drift by several minutes or hours over time. Reconnecting to the internet usually fixes this within a few minutes.

A third reason is an incorrect time zone setting. If your computer is set to a time zone far from your actual location, the clock will display the correct time for that zone but the wrong time for where you are. This is straightforward to fix by updating the time zone setting.

When to replace your computer's internal battery

If you change the time, restart your computer, and the clock is wrong again, your CMOS battery is likely dead. This is not an emergency—your computer will work fine otherwise—but the clock will never stay correct until the battery is replaced.

Replacing a CMOS battery requires opening your computer's case, which involves disconnecting power and sometimes removing several panels or components. If you are not comfortable doing this yourself, take your computer to a repair shop. The battery itself costs between $5 and $15, but labor will add to that cost. Many repair shops can do this in under an hour.

If your computer is still under warranty, contact the manufacturer before opening it yourself, as opening the case may void the warranty.

Syncing your clock with internet time servers

If you want your computer to always have the correct time without manual adjustment, make sure "Set time automatically" (Windows) or "Set date and time automatically" (Mac) is turned on. This setting tells your computer to check with an NTP server periodically and correct any drift.

This automatic sync works best when your computer is connected to the internet regularly. If you use your computer offline for long periods, the clock may drift slightly, but it will resync the next time you connect. The drift is usually only a few seconds per day, so it is rarely noticeable.

If automatic sync is on but your clock is still wrong, your internet connection may be unstable, or your computer may not be reaching the NTP server. Restart your computer and check your internet connection. If the problem persists, you can manually set the time as described above.

Frequently Asked Questions

Why does my clock reset every time I restart my computer?

Your computer's internal battery (CMOS battery) is likely dead or failing. This small battery keeps the clock running when your computer is off. When it fails, the clock reverts to a default date and time on each restart. A repair technician can replace it, usually in under an hour.

Can I change my computer's time zone without changing the actual time?

Yes. On Windows, go to Settings > Time & Language > Time zone and select your zone from the dropdown. On Mac, open System Settings > General > Date & Time and change the time zone. The displayed time will adjust automatically to match your new zone.

What if my computer's clock is off by several hours?

Check your time zone setting first—an incorrect zone is the most common cause of large time differences. If the zone is correct, turn off automatic time sync, manually set the correct time, and turn automatic sync back on. If the clock drifts again after restart, your internal battery may be failing.

Does changing my computer's clock affect my files or programs?

Changing the time can affect file timestamps and some programs that rely on accurate time, like email clients or security software. Avoid changing the time frequently. If you need to adjust it, do so once and let automatic sync take over.

Can I set my computer to a different time zone than my location?

Yes, you can set any time zone you want, but your computer will display the time for that zone, not your local time. This is useful if you work with people in other zones, but it can be confusing for daily use. Most people keep their computer set to their actual location's time zone.