In today's digital world, there's often a need to expand your workspace when a single screen is no longer physically sufficient. Situations where you urgently need to connect a second display, but only have a spare laptop, are common in offices and at home. Fortunately, wireless technology allows you to turn a laptop into a full-fledged monitor without the need for expensive HDMI or VGA cables.
Using a laptop as a second screen Wi-Fi opens up new horizons for multitasking, allowing you to display charts, instant messaging apps, or reference information on a separate panel. This method is especially relevant for owners of Ultrabooks lacking video outputs, or those working in coworking spaces and cafes. The main advantage is the freedom from cable length and a clutter-free workspace.
However, it is worth understanding that the quality of image transmission directly depends on the bandwidth of your local networkIf your router is old or overloaded, input lag can make working with dynamic content, such as videos or games, uncomfortable. For static work with text, code, or spreadsheets, this method is ideal and ensures high productivity.
Technical requirements and network preparation
Before beginning setup, ensure that both devices—the main computer and the laptop/monitor—are connected to the same wireless network. Using guest Wi-Fi with client isolation will prevent the devices from discovering each other, as the router will block direct packet exchange between them.
The best option is to use a range 5 GHz, which provides higher data transfer rates and lower latency compared to the congested 2.4 GHz band. If your router supports the standard Wi-Fi 6 (802.11ax), this will significantly improve connection stability, especially in apartment buildings with many neighboring networks.
It's also important to keep in mind that transmitting a video stream over the air consumes more power, so it's recommended to keep laptops connected to chargers. The battery may drain faster than usual due to the active Wi-Fi module and the processor, which will be busy decoding the video stream in real time.
⚠️ Note: If you're using a corporate network with strict security rules, your system administrator may block ports required for screen sharing (e.g., UDP ports). In this case, creating a direct Wi-Fi connection or using a hotspot from one of your laptops may be your only option.
Built-in Windows tools: Project to this PC
Windows 10 and 11 operating systems have built-in functionality for turning a laptop into a wireless display, eliminating the need for third-party software. This feature is based on Miracast over Infrastructure technology, which allows streaming over a local network, not just a Wi-Fi Direct connection.
To activate receiver mode on a laptop that will act as a monitor, go to the menu Start → Settings → System → Project to this PCIf the menu items are grayed out and inactive, you will need to install the "Wireless Display" component via the "Additional Components" menu in the "Apps & Features" section.
After enabling the feature, select visibility settings: you can allow connections from any devices on secure networks or require a PIN for each new session. On the main computer, press the key combination Win + Kto bring up the connection panel and select your receiver laptop from the list.
☑️ Setting up a built-in Windows projector
It's worth noting that this method works best in the Windows ecosystem. Attempting to connect macOS or Android devices via Windows' built-in mechanism may fail without the use of special emulators or third-party drivers.
Third party solutions: Spacedesk and Splashtop
When built-in tools are not enough or cross-platform support is required, specialized applications come to the rescue. Spacedesk is one of the most popular solutions for using any laptop with a browser or client as a second monitor. The program creates a virtual video adapter that streams images over a TCP/IP network.
To use, you need to install the SERVER driver on the main computer and the CLIENT driver on the laptop monitor. The application automatically detects devices on the network. The main advantage is support for multiple connections: you can turn several old laptops or tablets into displays, creating a huge video wall.
The alternative is Splashtop Wired XDisplay or its wireless counterparts, which often offer better performance in less-than-ideal Wi-Fi conditions due to more aggressive video stream compression. However, free versions of such programs often have session time or image quality limitations.
| Program | Platforms | Latency | Price |
|---|---|---|---|
| Spacedesk | Windows, Web, Android, iOS | Average | For free |
| Splashtop | Windows, macOS, Linux | Low | Paid subscription |
| Deskreen | Cross-platform | Depends on the browser | Open Source |
| Windows Native | Windows 10/11 | Low (in LAN) | Built-in |
Why might Spacedesk not work?
If Spacedesk doesn't detect your devices, check your Windows Firewall. Antivirus software often blocks incoming connections to the port used by the program (usually 4343). You need to add an exception rule for the spacedeskService.exe executable.
Using Apple laptops and macOS
Apple owners are in a better position thanks to the feature Sidecar, which allows you to use your iPad as a second monitor, but the situation is more complicated for a MacBook. MacOS natively cannot accept a video signal via video input, as the Thunderbolt and HDMI ports on the MacBook only output. However, there are software workarounds.
One solution is to use an app Luna Display or a free analogue DeskreenDeskreen is notable for the fact that it only requires installation on the main computer, while the laptop monitor can be any platform, even Linux or ChromeOS, since display occurs through a web browser.
To set up Deskreen, simply download the program to the host Mac, launch it, and scan the QR code on the receiving laptop's screen. It's important to ensure a reliable connection, as macOS is very sensitive to packet loss during video stream transmission, which can cause the mouse cursor to become out of sync.
⚠️ Note: When using a MacBook as an image receiver via third-party software, the system may require permissions for screen recording and local network access in the privacy settings. Without these permissions, streaming will not work.
Performance optimization and lag elimination
Even with an ideal setup, a wireless connection may suffer from micro-stuttering. To minimize latency, it's recommended to reduce the transmitted image resolution or frame rate in the transmitting software settings. For office work, 30 FPS and a resolution of 1920x1080 are sufficient.
Close all heavy background processes on the laptop that's acting as a monitor. A browser with dozens of tabs open, torrents, and Windows updates can consume CPU and network resources, negatively impacting cursor smoothness.
If you're using a dual-band router, make sure both devices are using the 5 GHz band and aren't switching to 2.4 GHz due to a weak signal. Disabling power saving for your Wi-Fi adapter in Device Manager also helps: find your adapter, go to Properties, and in the "Power Management" tab, uncheck the box next to "Allow power off device."
Comparison of wired and wireless connections
Despite the convenience of Wi-Fi, it's important to remember that a cable always provides better stability. If you plan to use your laptop as a permanent second monitor for color or video editing, a wireless connection may not be suitable due to compression artifacts.
A wired connection via a video capture card (such as cheap USB cards from AliExpress) turns a laptop into a monitor with virtually zero latency. This requires purchasing additional hardware, but the results are worth it for professional work.
However, for temporary tasks, presentations, or desktop extensions for chats and monitoring, a Wi-Fi solution is unrivaled in ease of deployment. You can set up a dual-monitor setup in seconds anywhere there's a power outlet.
⚠️ Note: Program and operating system interfaces are subject to change. Menu item locations and feature names may differ in newer versions of Windows or macOS. Always check the official documentation from the software developers for the most up-to-date information.
Frequently Asked Questions (FAQ)
Can I use my laptop as a monitor via Wi-Fi for gaming?
Technically, this is possible, but highly not recommended for fast-paced shooters or racing games. Even on a good network, input lag will range from 30 to 100 ms, making gaming uncomfortable. For turn-based strategy or card games, this option is perfectly acceptable.
Does connecting a second laptop affect internet speed?
Yes, because the video stream takes up a significant portion of your local network's bandwidth. If your router is weak, file download speeds on other devices may drop. However, the internet connection itself (the connection to the external network) is minimally impacted, as the stream is transmitted within the LAN.
Does this method work if there is no access to the router?
Yes, you can create a hotspot on your main computer and connect your laptop/monitor to it. This will create a direct wireless network between the devices, which will even improve connection stability by eliminating interference from other devices on the network.
Why doesn't my laptop see another computer for connection?
The most common cause is different subnets or a firewall blocking the connection. Make sure the network profile is set to "Private" and not "Public," and that device discovery and file and printer sharing are enabled in the network settings.