Change the system time and date on Windows or Mac
The fastest way to change your computer's clock depends on which operating system you use. On Windows, right-click the time in the bottom-right corner of your screen and select Adjust date/time. On Mac, click the Apple menu, go to System Settings (or System Preferences on older versions), then select General and Date & Time. Both systems let you set the time manually or turn on automatic synchronization so your computer updates the clock on its own.
Most people should leave automatic time updates turned on. Your computer syncs with internet time servers, which keeps your clock accurate without any work from you. Manual changes are useful only when your computer's clock has drifted noticeably or when you need to test something on a specific date.
Key Takeaways
- On Windows, right-click the system clock and choose Adjust date/time to change the time manually or enable automatic updates.
- On Mac, open System Settings, go to Date & Time, and toggle Set date and time automatically on or off.
- Automatic time synchronization keeps your clock accurate and is the default setting on both Windows and Mac.
- If your clock keeps resetting or showing the wrong time after restart, your computer's battery may need replacement.
How to change the time on Windows 11 and Windows 10
Right-click the time display in the bottom-right corner of your taskbar. A menu will appear with several options. Click Adjust date/time to open the date and time settings panel.
In the settings window, you will see a toggle for Set time automatically. If this toggle is already on (blue), your computer is syncing with an internet time server and you do not need to do anything. If you want to set the time manually, turn this toggle off first. Once it is off, a new option called Set the time manually will appear. Click that option and enter the correct hour, minute, and second. Click the checkmark to confirm.
You can also change the date in the same window. Below the time settings, you will see the current date. Click on it to open a calendar, select the correct date, and click the checkmark. When you are finished, close the settings window. Your changes take effect when ready.
How to change the time on Mac
Click the Apple menu in the top-left corner of your screen. Select System Settings (on macOS Ventura and newer) or System Preferences (on older versions). In the sidebar, click General, then select Date & Time.
You will see a toggle labeled Set date and time automatically. If this is on, your Mac is already syncing with an internet time server. To set the time manually, click the toggle to turn it off. A clock interface will appear where you can click and drag the hour and minute hands to the correct time, or click the time display to type in the numbers directly. Select the correct date from the calendar below if needed.
Once you have set the time and date, close the settings window. Your Mac will use the time you entered until you turn automatic synchronization back on or change it again manually.
When your computer clock keeps resetting
If you change the time but it reverts to the wrong time after you restart your computer, the problem is usually a failing CMOS battery. This is a small battery inside your computer that stores the date and time when the power is off. When this battery dies, your computer cannot remember the correct time between shutdowns.
You can work around this temporarily by turning on automatic time synchronization, which will correct the clock as soon as you connect to the internet. However, a CMOS battery replacement is inexpensive and permanent. On a desktop computer, you can replace it yourself — it is a coin-sized battery that pops out of the motherboard. On a laptop, you may need to take it to a repair shop, though some models allow you to access it without disassembling the entire machine.
If your computer is still under warranty, contact the manufacturer before attempting any repairs yourself.
Changing the time zone on your computer
Your computer's time zone setting controls what time is displayed based on your location. On Windows, open the date and time settings (right-click the clock and select Adjust date/time), scroll down to Time zone, and click the dropdown menu to select your location. On Mac, open System Settings, go to General and Date & Time, and click the Time zone dropdown to choose your region.
If you travel frequently or work with people in other time zones, you can add additional clocks to your computer. On Windows, open the date and time settings and scroll to Related links, then click Add clocks for different time zones. On Mac, open the Clock app and click the plus button to add a new city. Your computer will then display multiple clocks so you can see the time in different locations at once.
Why your computer's clock matters
An accurate system clock affects more than just telling time. Your computer uses it to timestamp files, schedule tasks, and verify security certificates for websites. If your clock is significantly off, websites may refuse to load, emails may not send, and file backups may fail. Some programs also use the system time to enforce license expiration dates, so an incorrect clock can lock you out of software you own.
This is why automatic time synchronization is the default on modern computers. Keeping it on ensures your clock stays accurate without any effort on your part, and it prevents the problems that come with a drifting clock.
Frequently Asked Questions
Will changing my computer's clock affect my files or programs?
Changing the time will update the timestamp on new files you create after the change, but it will not delete or damage existing files. Some programs that track licenses or subscriptions may behave oddly if the clock is set far in the past or future, but they will return to normal once the correct time is restored.
Can I set different times for different user accounts on the same computer?
No. The system clock is shared across all user accounts on a computer. If one account changes the time, all accounts see the new time. However, you can set different time zones for different accounts on some systems, which will display the time differently without actually changing the system clock.
What if I cannot find the date and time settings?
On Windows, you can also reach date and time settings by typing "date and time" into the search box on your taskbar. On Mac, you can search for "Date & Time" using Spotlight (press Command + Space). Both methods will open the settings panel directly.
Is it safe to turn off automatic time synchronization?
It is safe, but not recommended. Turning it off means your clock will drift over time and you will need to correct it manually. Leave automatic synchronization on unless you have a specific reason to set the time manually, such as testing software that depends on a particular date.