Why Your Computer Clock Drifts and How to Fix It
Your computer's clock can fall behind or jump ahead for several reasons: the internal battery that keeps time when the machine is off may be dying, your system didn't sync with a time server when it started up, or you manually changed the time and forgot to change it back. The fix depends on whether you use Windows or macOS, but both operating systems can sync automatically with internet time servers so you never have to set the clock by hand again.
The fastest way to correct the time is to let your computer do it automatically. If that does not work, you can set the time manually in a few clicks. Either way, the process takes less than a minute.
Key Takeaways
- Windows and macOS both have a setting to sync your clock automatically with internet time servers, which is the most reliable fix.
- On Windows, open Settings, go to Time & Language, and turn on "Set time automatically" if it is off.
- On macOS, open System Settings, click General, then Date & Time, and check that "Set date and time automatically" is enabled.
- If automatic sync is already on but your clock is still wrong, restart your computer to force a fresh sync with the time server.
- If you need to set the time manually, you can do so in the same settings menu, but automatic sync is better because it corrects drift over time.
Reset the Clock on Windows 11 or Windows 10
The easiest method is to turn on automatic time sync. Open the Start menu and type "Settings" into the search box, then click Settings. In the left sidebar, click "Time & Language." On the right side of the window, you will see a section called "Time." Look for the toggle that says "Set time automatically" — if it is already blue and switched on, your computer should be syncing with a time server. If it is gray and off, click it to turn it on.
Wait a few seconds for the sync to happen. Your clock should now show the correct time. If it does not, restart your computer by clicking the Start menu, clicking the power icon, and selecting "Restart." When your computer boots back up, it will contact the time server again and pull the correct time.
If you need to set the time manually instead, stay in the Time & Language settings and scroll down to find "Change date and time." Click that option, and you will see fields where you can type in the correct date and time. Type the values you need, then click "Change." Manual time entry is useful if you are offline, but once you reconnect to the internet, turn automatic sync back on so your clock stays accurate.
Reset the Clock on macOS
Open the Apple menu in the top-left corner of your screen and click "System Settings." In the left sidebar, click "General." In the main panel on the right, click "Date & Time." You will see a checkbox that says "Set date and time automatically" — make sure it is checked. If it is already checked, your Mac is syncing with Apple's time servers and should show the correct time within a few seconds.
If the checkbox is unchecked, click it to turn on automatic sync. Your Mac will contact the time server and update the clock. If the time is still wrong after you enable automatic sync, restart your Mac by clicking the Apple menu, clicking "Shut Down," waiting for the machine to power off, and then pressing the power button to turn it back on.
To set the time manually on macOS, uncheck the "Set date and time automatically" box in the Date & Time settings. You will then see fields where you can click and type the correct date and time. Enter the values you need and close the settings window. Remember to turn automatic sync back on once you are done, so your clock does not drift again.
What to Do If Automatic Sync Is On but the Time Is Still Wrong
If you have turned on automatic time sync but your clock still shows the wrong time, the problem is usually that your computer has not contacted the time server yet. The fastest fix is to restart your computer. When it boots up, it will when ready try to sync with the time server before anything else loads.
If restarting does not work, check that you are connected to the internet. Your computer cannot sync with a time server if it has no network connection. Open your browser and visit any website to confirm you have internet access. If you are offline, connect to Wi-Fi or plug in an ethernet cable, then restart your computer.
On rare occasions, your computer's internal clock battery may be failing. If the time is always wrong when you turn on your computer, even after you set it correctly and restart, the battery that keeps time when the machine is off may need replacement. This is a hardware issue that requires opening the computer, so contact a repair technician or the manufacturer for help.
Why Automatic Sync Is Better Than Manual Time Entry
Computer clocks are not perfectly accurate — they lose or gain a few seconds every day, even when they are working normally. If you set the time manually once, it will slowly drift out of sync again. Automatic time sync fixes this by checking with an internet time server every time your computer starts up and periodically while it is running. The time server is synchronized with atomic clocks, so it is always correct.
Leaving automatic sync on means you never have to think about the clock again. Your computer will stay accurate whether you restart it once a week or once a month. The only time you should turn off automatic sync is if you are deliberately running your computer on a different time zone for testing purposes, and even then, you should turn it back on when you are done.
Changing Your Time Zone
If your clock shows the correct time but it is in the wrong time zone, you need to change your time zone setting, not the clock itself. On Windows, open Settings, go to Time & Language, and scroll down to "Time zone." Click the dropdown menu and select your time zone from the list. On macOS, open System Settings, click General, then Date & Time, and click the "Time zone" dropdown to select your region.
Once you change the time zone, your clock will automatically adjust to show the correct local time. You do not need to restart your computer. If you travel frequently and want your computer to automatically detect your time zone, some newer versions of Windows and macOS have a setting for this — look for "Set time zone automatically" in the same menu where you change the time zone manually.
Frequently Asked Questions
Why does my computer clock keep losing time even though automatic sync is on?
Automatic sync only updates your clock when your computer starts up or periodically while it is running. If your computer is on for many days without restarting, the clock can drift slightly. Restart your computer once a week to force a fresh sync. If the clock is losing more than a few minutes per day, your internal clock battery may be failing and may need replacement by a technician.
Can I set my computer to a different time zone without changing the actual time?
No. When you change the time zone, the clock automatically adjusts to show the correct local time for that zone. If you need your computer to show a time that does not match your actual location, you would have to turn off automatic sync and set the time manually, but this is not recommended because the clock will drift.
What happens if I turn off automatic time sync?
Your clock will stop updating automatically and will slowly drift out of sync. You will have to set the time manually whenever it becomes noticeably wrong. Automatic sync is always the better choice unless you have a specific reason to turn it off, such as testing software that depends on a specific time.
Does resetting the clock affect my files or programs?
No. Changing the system time does not delete files, uninstall programs, or cause any data loss. However, changing the time backward can occasionally confuse backup software or file sync programs, so it is best to set the time forward or use automatic sync instead.
Why is my computer's time different from my phone's time?
Your phone and computer may sync with different time servers or at different intervals. If the difference is only a few seconds, this is normal. If it is more than a minute, turn on automatic sync on both devices and restart them. If your phone is on a different time zone setting than your computer, that will also cause a difference.