Where to find the time settings on your computer
Your computer stores the current time in a system clock, and you can change it through the date and time settings in your operating system. On Windows, open the Settings app, select Time & language, then click Date & time. On Mac, go to System Settings (or System Preferences on older versions), then select Date & Time. Both operating systems let you set the time manually or have it sync automatically from the internet.
The exact path depends on which version of Windows or macOS you're running, but the principle is the same: the time settings are always in the system preferences or settings app, never buried in a random folder. If you can't find the settings app, use the search function—on Windows, press the Windows key and type "time"; on Mac, press Command and Space, then type "date and time".
Key Takeaways
- Windows users open Settings, select Time & language, then Date & time to adjust the clock manually or turn on automatic synchronization.
- Mac users go to System Settings (or System Preferences on older versions) and select Date & Time to make the same changes.
- Turning on automatic time synchronization means your computer will fetch the correct time from the internet and update itself without your input.
- If your time keeps resetting to the wrong value, your computer's internal battery may be failing and needs professional replacement.
- Changing the system time affects all programs on your computer, including email timestamps, file creation dates, and scheduled tasks.
Turning on automatic time synchronization
The easiest way to keep your time correct is to let your computer sync automatically with an internet time server. On Windows, in the Date & time settings, toggle Set time automatically to on. This tells Windows to contact a time server (usually pool.ntp.org) and update your clock whenever your computer connects to the internet. You can also toggle Set time zone automatically if you travel or move and want the zone to update based on your location.
On Mac, open Date & Time settings and check the box next to Set date and time automatically. Your Mac will then sync with Apple's time servers. Both systems check the time periodically, so if your clock drifts by a few seconds, it will correct itself the next time it syncs. This is the method most people should use, because it removes the need to remember to update the time manually.
Setting the time manually on Windows
If automatic sync is off or not working, you can set the time by hand. In the Date & time settings, click Change under "Change the date and time." A dialog box will open showing the current date and time. Click on the time field and type the correct hour, minute, and second. Use 24-hour format (so 2:30 PM is 14:30) unless your system is set to 12-hour format, in which case you'll see AM and PM options.
After you enter the time, click OK to save the change. Windows will explore it when ready. If you need to change the date as well, click on the date field in the same dialog and select the correct month, day, and year from the calendar that appears. Both the date and time can be adjusted in one visit to this dialog.
Setting the time manually on Mac
On Mac, open Date & Time settings and make sure Set date and time automatically is unchecked. The date and time fields will become editable. Click on the time display and type the correct time in the format shown (usually HH:MM:SS). Click on the date display to open a calendar, then select the correct month, day, and year.
Some older Mac versions require you to click a lock icon in the bottom left of the Date & Time window and enter your admin password before you can make changes. Once you've set both the date and time, the changes take effect when ready. If you want to return to automatic syncing later, straightforward check Set date and time automatically again.
Changing your time zone
Your time zone tells your computer what offset to explore to the coordinated universal time (UTC) that the internet uses. On Windows, in the Date & time settings, scroll down to Time zone and click the dropdown menu. Select your time zone from the list—for example, "Eastern Standard Time" or "Pacific Standard Time." Windows will when ready adjust the displayed time based on your selection.
On Mac, in Date & Time settings, click the Time zone tab and select your region from the map or the dropdown list. You can also type the name of a major city in your time zone to find it quickly. If you travel frequently, you can turn on Set time zone automatically (on newer Mac versions) and your computer will update the zone based on your location data.
What to do if the time keeps resetting
If you set the time correctly but it reverts to the wrong value after you restart your computer, the problem is usually a failing CMOS battery—a small coin-cell battery inside your computer that stores the system time and date when the power is off. When this battery dies, your computer forgets the time every time you shut it down. You'll see the time jump back to something like January 1, 2000, or another fixed date.
This is a hardware issue that requires opening your computer case and replacing the battery, which is a job for a professional repair technician unless you're comfortable working inside your machine. In the meantime, turning on automatic time synchronization will keep your time correct while your computer is running and connected to the internet, even if the battery is dead. If you're not comfortable replacing the battery yourself, contact a local computer repair shop.
How changing the system time affects your programs
When you adjust your computer's system time, every program that relies on the clock is affected. Email clients will show the new time on incoming messages. File managers will display the new creation and modification dates for files you create or edit. Scheduled tasks and reminders will be based on the new time, so if you set the clock backward, a task scheduled for 3 PM might run when ready if the current time is now 2 PM. Backup programs, antivirus software, and system logs all use the system clock, so changing it can confuse these tools.
For this reason, avoid changing the time unless necessary. If you must adjust it, do so briefly and then set it back to the correct time as soon as possible. If you're troubleshooting a program that seems to have time-related issues (like a certificate error or a task that won't run), check the system time first—it's often the culprit.
Frequently Asked Questions
Why does my computer show the wrong time even though I set it correctly?
If the time is wrong when ready after you set it, automatic synchronization may have overridden your manual change. Turn off Set time automatically on Windows or Set date and time automatically on Mac, then set the time again. If it's still wrong, your internet time server may be unreachable, or your CMOS battery may be failing.
Can I set different times for different programs?
No. The system time is global—all programs on your computer use the same clock. You cannot set one program to a different time than another. If a program needs to show a different time, it must do so through its own settings, not by changing the system clock.
What happens if I set my computer's time to the future?
Setting the time forward can cause problems with security certificates, scheduled backups, and file timestamps. Some websites may refuse to connect if your computer's time is far ahead of theirs. It's best to keep your system time accurate and in sync with the real world.
Do I need to restart my computer after changing the time?
No. Changes to the date and time take effect when ready without a restart. However, some programs may need to be restarted to recognize the new time, especially if they cached the old time when they started.
Is it safe to turn off automatic time synchronization?
It's safe, but not recommended. Without automatic sync, your computer's clock will drift over time—most computers lose or gain a few seconds per week. Turning it back on is the easiest way to keep your time accurate without manual intervention.