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Door staff@engadget.com (Kari Paul) - 09 Nov 2026
If both your primary computer and the spare laptop you want to use as a second monitor are running Windows 10 or 11, extending or mirroring them is quite simple due to the operating systems' built-in wireless casting tools. These rely on Miracast, a functionality that enables connections between devices via Wi-Fi and requires only a quick workflow to set up.
To activate it, go to your spare laptop, open Settings, then System, then Projecting to this PC. Click Optional features, then View features, then select Wireless Display to add it. Once it installs, return to the same page and set it to Available everywhere, and open the Wireless Display app.
Now, you're ready to mirror or extend your display. On your main computer, press the Windows key + K, select the spare laptop from the list of available displays, enter the PIN and allow keyboard and mouse input. You can then choose to duplicate your screen or extend it, and you can switch anytime with Windows key + P. Keep in mind, this method of connecting your devices does require Wi-Fi on both machines, and you may experience some lag. Therefore, while it's great for presentations or organizing large numbers of tabs, it may not be the best choice for gaming.
To activate it, go to your spare laptop, open Settings, then System, then Projecting to this PC. Click Optional features, then View features, then select Wireless Display to add it. Once it installs, return to the same page and set it to Available everywhere, and open the Wireless Display app.
Now, you're ready to mirror or extend your display. On your main computer, press the Windows key + K, select the spare laptop from the list of available displays, enter the PIN and allow keyboard and mouse input. You can then choose to duplicate your screen or extend it, and you can switch anytime with Windows key + P. Keep in mind, this method of connecting your devices does require Wi-Fi on both machines, and you may experience some lag. Therefore, while it's great for presentations or organizing large numbers of tabs, it may not be the best choice for gaming.