Many users are faced with a situation where they need to expand their workspace, but do not have an additional display at hand. A way out of this situation may be to use an existing laptop as a second screen for a desktop computer. This task seems difficult since the standard HDMI port on most portable devices only outputs a signal, not receives it.
However, modern technologies make it possible to solve this problem both in software and through special hardware adapters. It is important to understand that there is no universal “plug and forget” method, and the method you choose depends on your operating system, the type of cables used, and acceptable image latency. In this article, we'll look at all the available options, from built-in Windows features to third-party utilities and hardware solutions.
Why can't you just plug in an HDMI cable?
The most common mistake newbies make is trying to connect two devices with a standard HDMI cable, expecting the laptop to immediately display the image. In reality, the port is on the body of most laptops (including models Lenovo, Dell, HP) is a day off. It is designed to transmit images from the screen of a laptop PC to an external projector or TV, but cannot receive a signal from the outside.
The only exceptions are rare high-end gaming models equipped with a port HDMI IN, but they are very difficult to find on the secondary market. If you simply connect two devices with a cable, nothing will happen, since the video card of the second computer does not have the physical ability to decode the incoming stream through this interface. The only way is to use software data transfer protocols or special video captures.
It is important to consider that even if there is a specialized port, drivers may not support monitoring mode without additional configuration. Therefore, before purchasing a cable, you should check the specifications of your model in the manufacturer's documentation. In most cases, you will have to resort to more complex but effective methods.
⚠️ Attention: Trying to connect a signal source to the HDMI output port through adapters without active signal conversion may lead to overheating of the video card or failure of the port. Always check the port type before connecting.
Using the built-in Project to This Computer feature
If both devices are running Windows 10 or 11, the easiest way is to use the built-in Project to This PC feature. This technology uses the Miracast protocol to transmit images over a Wi-Fi network. For this feature to work, your laptop must support 802.11ac or later wireless adapters.
To activate monitor mode on a portable device, you need to go to Settings → System → Project to This PC. If the controls you want are grayed out, click the More Features link and install the Wireless Display feature. After that, select “Available everywhere on secure networks” from the drop-down menu.
On your main computer, click Win + Kto open a list of available devices and select your laptop. The screen will expand or duplicate depending on the settings you select. This method is convenient because it does not require the installation of additional software, but may suffer from delays at low network speeds.
- ✅ Requires only Wi-Fi adapters on both devices
- ✅ Completely free and built into the system
- ❌ There may be delays (lag) when watching dynamic videos
- Wired HDMI
- Wireless Miracast
- Third party software
- Haven't tried it yet
Software solutions for remote access
For users who need higher connection stability or who work in macOS and Linux environments, specialized utilities are the ideal solution. Programs like Spacedesk, Duet Display or Deskreen allow you to turn a laptop into a monitor via a local network or even via the Internet. They work on the principle of a remote desktop, but are optimized specifically for using a second screen.
Installation Spacedesk takes a few minutes: you need to install the driver on the main PC and the client application on the laptop. Once launched, they will automatically find each other on the same network. A special feature of these programs is the ability to customize the resolution, refresh rate, and even color to reduce network load. For example, you can lower the bitrate to improve smoothness.
It's worth noting that some of these services, such as Duet Display, offer paid subscriptions to unlock high-performance features and work via a USB cable. This minimizes the impact of the wireless network on latency. Free analogues often have restrictions on screen resolution or the number of connected devices.
- 🚀 Supports operation via USB cable to reduce latency
- 🎮 Suitable for graphics and light gaming
- 🛠️ Requires installation of additional software
☑️ Preparing to set up Spacedesk
⚠️ Attention: When using wireless solutions, make sure that both devices are connected to the same 5GHz router and not 2.4GHz, otherwise the bandwidth may not be enough for smooth viewing.
Hardware method: video capture for professional use
If you need to use your laptop as a monitor for gaming consoles or work with minimal latency, software methods will not work. The only reliable solution in this case is to use a Video Capture Card. This is a small device that plugs into a laptop's USB port and receives an HDMI signal from another computer or console.
The cost of such devices varies from budget Chinese models to professional solutions from Elgato. Budget options that work as webcams can produce a latency of 100-200 ms, which is unacceptable for fast-paced games, but great for watching videos or working with text. For professional tasks, models with support for 4K and high frame rates are required.
The setup is extremely simple: connect the HDMI cable from the source to the capture, and the capture into the USB port of your laptop. The system will recognize the device as a webcam. All you have to do is open the viewer program (for example, OBS Studio or the standard Camera application) and select the video source.
| Device type | Latency (approx.) | Suitable for games | Difficulty setting up |
|---|---|---|---|
| Windows Firmware | 50-100 ms | No | Low |
| Spacedesk (Wi-Fi) | 80-150 ms | No | Average |
| Budget video capture | 100-200 ms | Weak | Low |
| Professional capture | 10-30ms | Yes | Average |
Which video capture should I choose to start with?
If your budget is limited, pay attention to models with a UVC (USB Video Class) chipset. They do not require driver installation and work immediately after connection. Avoid devices with 1080p 30Hz resolution if you plan to work with fast-paced content, as flickering will be noticeable.
Optimizing settings for maximum performance
Once the connection is established, the display settings must be adjusted correctly to avoid blurring or desynchronization. In Windows display settings, make sure that the second screen resolution is set to the native resolution of your laptop. If you are using laptop with matrix 1920×1080, forcing a higher resolution will result in scaling and loss of clarity.
It is also worth paying attention to the screen operating mode. In the display properties, you can select "Extend these screens" or "Duplicate". For work, the second option is rarely useful due to different matrix resolutions, and the first allows you to drag windows between devices. Disable animations and transparency in system settings if you notice stuttering when moving windows.
For wireless connections, it is critical to disable power saving on the network adapter. Go to Device Manager → Network Adapters → Properties → Power Management and uncheck “Allow the computer to turn off this device to save energy.” This will prevent short-term connection interruptions when idle.
- 🔋 Disable power saving on your network adapter
- 📺 Set native screen resolution
- ⚡ Close background apps that consume bandwidth
If you're using your laptop as a monitor, close the lid or set it to "Sleep only when lid is closed" mode so that the screen doesn't go dark while you're working, but the system doesn't go into sleep mode.
Comparison of methods and final recommendations
The choice of method depends on your specific tasks. If you just need more space for working on documents or coding, Windows built-in or Spacedesk are ideal. They are easy to set up and do not require additional costs. However, for gaming or watching videos in high quality, it is better to use hardware video capture.
Don't forget about the delay factor. Hardware video capture provides minimal latency, comparable to connecting a conventional monitor, while software methods always have a certain inertia. This is a critical factor if you plan to use the second screen for fast-paced action.
Ultimately, turning your laptop into a monitor is a great way to save money on additional hardware. The main thing is to choose a method that meets your technical capabilities and image quality requirements. Experiment with settings to find the perfect balance between smoothness and quality.
⚠️ Attention: When using the laptop as a monitor for an extended period of time with the lid closed, make sure that the cooling system does not overheat, especially if the laptop is placed on a soft surface such as a blanket or sofa.
Can a laptop be used as a monitor for PlayStation 4?
Connecting an HDMI cable directly will not work. To do this, you will need to use a video capture card connected to your laptop. Software methods (Miracast) do not support video transmission from consoles directly.
Why does the image on my laptop flicker?
This is most often caused by a low refresh rate (30Hz) when using budget capture cards or an unstable Wi-Fi connection. Try switching to cable or using a wired connection for Spacedesk.
Does this method work on macOS?
The built-in projection feature in Windows does not work directly on macOS. For Mac, you need to use third-party applications such as Duet Display or Luna Display, which are paid but provide stable performance.
Is it possible to play games through a laptop like a monitor?
Only if you are using a professional low latency video capture card. Software methods will give a noticeable lag, which will make dynamic games (shooters, racing) almost impossible, but you can play strategy or turn-based games.
Using a video capture card is the only way to get latency comparable to a regular monitor, making this method the only one suitable for gaming.