System “uptime” refers to the exact amount of time that your computer has been continuously running since its last reboot. Knowing your uptime is highly useful for troubleshooting purposes—especially if your PC is acting sluggish, a program is crashing, or you suspect a memory leak. In many cases, Windows computers can run for weeks or even months without a true shutdown because the “Shut Down” button in Windows 11 often just places the PC into a deep hibernation state (known as Fast Startup).
If you want to know exactly how long your PC has been running, Windows 11 provides a quick and easy way to check your uptime.
In this guide, you will learn the fastest way to view your system uptime using the Task Manager.
How to Check Uptime in Task Manager
The Task Manager provides a live counter of your computer’s uptime down to the exact second.
- Open the Task Manager by right-clicking on the Start button and selecting Task Manager from the menu. (Alternatively, press Ctrl + Shift + Esc on your keyboard).
- If your Task Manager opens in a small window with no tabs, click the More details arrow at the bottom.
- Click on the Performance tab on the left sidebar (it looks like a small line graph).
- Click on CPU near the top left.
- Look toward the bottom of the window, beneath the large moving graph. Locate the text label that says Up time.
The numbers listed next to “Up time” indicate Days:Hours:Minutes:Seconds. For example, if it reads 14:08:22:45, your computer has been running for 14 days, 8 hours, 22 minutes, and 45 seconds without a true restart.
Why Is My Uptime So High?
If you recently clicked “Shut Down” but your uptime says your PC has been running for 15 days, do not panic. By default, Windows 11 uses a feature called “Fast Startup.” When you click Shut Down, Windows does not actually turn off completely; instead, it saves the current system state to your hard drive so it can boot up faster the next time you press the power button. This means the uptime counter does not reset.
To truly reset your system uptime and give your PC a fresh start, you must click Restart instead of Shut Down. Restarting bypasses the Fast Startup feature, completely clears the RAM, shuts down the kernel, and starts the system entirely fresh, bringing your uptime back down to zero.