The fastest way to change your computer's time

On Windows, click the time in the bottom right corner of your screen, then select Change date and time settings. Toggle Set time automatically off, then click Change under "Set the date and time manually". Type in the correct time and click Save.

On Mac, open System Settings (or System Preferences on older versions), go to General, then Date & Time. Uncheck Set date and time automatically if it is checked, then click the lock icon and enter your password. Click the time field and type the correct time, or use the up and down arrows to adjust it.

Both operating systems also let your computer set the time on its own by syncing with an internet time server. This is usually the better choice if your time keeps drifting, because it means your computer will correct itself without you having to step in again.

Key Takeaways

  • Windows users click the time in the taskbar, turn off automatic time setting, and manually enter the correct time through the date and time settings panel.
  • Mac users open System Settings, navigate to Date & Time, disable automatic time setting, and adjust the time using the time field or arrow buttons.
  • Turning on automatic time synchronization prevents your computer's clock from drifting and removes the need to reset it manually.
  • Your computer's internal clock can lose or gain time over months, especially if automatic syncing is off, which is why periodic checks matter.

Why your computer's time drifts

Every computer has a small battery-powered clock inside called a CMOS battery that keeps time even when the machine is powered off. Over time, this battery weakens and the clock loses accuracy. If your computer sits unplugged for weeks or months, the time can be off by hours or even days when you turn it back on.

When automatic time syncing is turned on, your computer connects to a time server on the internet and corrects itself. This happens in the background without any action from you. If syncing is off, the drift just keeps building until you notice the time is wrong.

Turning on automatic time synchronization

On Windows 10 and 11, open Settings, go to Time & language, then Date & time. Look for the toggle labeled Set time automatically and make sure it is turned on. You should also see Set time zone automatically — turn that on too if you travel or move.

On Mac, the setting is in System Settings > General > Date & Time. Check the box next to Set date and time automatically. Your Mac will then sync with Apple's time servers whenever it connects to the internet.

Once automatic syncing is on, you do not need to touch the time again unless you change time zones. Your computer will stay accurate on its own.

Changing your time zone

If you move to a different time zone or travel, you may need to update your time zone setting separately from the actual time. On Windows, go to Settings > Time & language > Date & time and look for Time zone. Click the dropdown and select your new zone from the list.

On Mac, open System Settings > General > Date & Time and click Time zone. Type your city name or select it from the map. If you have Set date and time automatically turned on, your Mac will update the time zone based on your location when you connect to the internet.

Changing your time zone does not change the actual time on your computer — it just tells your computer how to display that time. If you are in New York and set your zone to Los Angeles, the clock will show three hours earlier, but the actual moment in time stays the same.

When to manually set the time instead

You should manually set the time if your computer is not connected to the internet and the clock is wrong. This happens most often with older laptops or machines that have been off for a long time. Manually setting the time is also necessary if your internet connection is down and you need the correct time right away.

If you find yourself resetting the time every few days, your CMOS battery may be failing. On a desktop computer, this is a replaceable part that costs between ten and thirty dollars. On a laptop, the battery is usually soldered to the motherboard and requires professional repair. In either case, it is worth having checked if the problem is frequent.

Syncing time across multiple devices

If you use multiple computers, tablets, or phones, they should all sync to the same internet time server automatically. This means they will all show the same time as long as automatic syncing is on and they are connected to the internet. You do not need to manually synchronize them.

If one device is consistently off by a few minutes or hours, check whether automatic time syncing is turned on for that device. If it is on but the device is still wrong after a restart, the device may have a hardware problem or may not be connecting to the internet properly.

Frequently Asked Questions

Why does my computer time keep changing on its own?

Your computer is syncing with an internet time server, which is normal and correct. If automatic syncing is on, your computer will adjust itself whenever it detects a difference. This is the intended behavior and keeps your clock accurate.

Can I set my computer to a different time than the actual time?

Yes, but you should turn off automatic time syncing first, or your computer will correct itself back to the real time. There is rarely a good reason to do this — most programs and websites rely on your computer showing the correct time.

What happens if I set my time zone wrong?

Your computer will display the wrong time, and programs that depend on time zones (like calendar apps and email) may show events at the wrong times. Changing your time zone back to the correct one fixes this when ready.

Does changing the time affect my files or programs?

Changing the time can confuse file backup programs and cloud syncing services, because they use timestamps to decide which version of a file is newest. Avoid changing the time if you can, and if you must, restart your backup and sync programs afterward.

How often should I check my computer's time?

If automatic syncing is on, you do not need to check it. If syncing is off, check it once a month or whenever you notice it seems wrong. If your computer loses more than a few minutes per month, the CMOS battery may need replacement.