Over the years, you’ve probably got a solid collection of laptops and tablets sitting around. Old MacBooks, Windows laptops, an iPad or two, or even an Android tablet, but you may be wondering if you could put those screens to good use.
The good news is it is possible to use many laptops and tablets as a second or external monitor.
Bad news? It’s not always as easy as just plugging in a cable. And while they won’t be as usable as dedicated portable monitors, they’ll work in a pinch.
So we’re breaking things down easy for you, and answering all of these questions so you have everything you need to know about using laptops, tablets, and phones as external displays.
Apple Devices (MacBook & iPad)
Image Source – Apple
Q1: Can I use my MacBook / an old MacBook as an external monitor for another Mac or Windows PC?
MacBook to Macbook Connectivity
Yes, it is possible to use an older MacBook as an external monitor for another Mac, although there are some limitations. Most MacBooks don’t have a dedicated video input port to simply connect another computer with an HDMI or USB-C cable and use the built-in screen as a display.
Apple does have native display-sharing features between Macs, but compatibility mainly depends on the specific Mac models/macOS versions. Even then, this feature only allows you to mirror one Mac screen to another Mac, not extend the display.
For older MacBooks that don’t support Apple’s native solutions, third-party software is a more practical workaround.
One of the more popular options is Luna Display, a hardware solution that transforms PCs, tablets, and Macs, into a secondary screen. The way it works is by plugging in a small hardware adapter to the primary Mac, and using the Luna app on the older Mac.
You can connect via Wi-Fi, Ethernet, USB, or Thunderbolt, but for lower latency, we’d recommend a wired connection.
Alternatively, Duet Display is another solid option to turn your Mac into a second display. This is a software solution that doesn’t need an additional dongle, and works with a wired or wireless connection to mirror or extend your MacBook to an older Mac display.
MacBook to Windows PC Connectivity
Using your older MacBook as a second display for a Windows PC is also possible, but you’ll need third-party software here. Duet Display and Luna Display works for both Mac to Mac and Mac to Windows connections, so they’re still solid options.
But if you’re after a free alternative, Deskreen works similarly and can stream a computer’s display to another device through a web browser. It works on both Windows and macOS, and all you need is to connect both to a Wi-Fi connection.
That said, primarily, this only works to mirror your Windows PC to the MacBook; if you want to extend your screen instead, you’ll need to use a Virtual Display Adapter which requires some extra setup.
But for both cases, Windows PC to Mac or Mac to Mac connections, these are primarily software-based solutions that aren't quite the same as connecting to a dedicated monitor.
That means that because the display is transmitted through software and a network or physical connection, performance and latency can vary. It won’t be as quick as a gaming monitor, but it will work.
Q2: Can I use my iPad as a second monitor for Mac / Windows PC?
iPad to Mac Connectivity
Yes! iPads and Macs work fantastically together, and with a feature called Sidecar, you can easily mirror or extend your Mac screen onto an iPad. To move a Mac window to your iPad, hover over the green full-screen button, then choose the “Move to iPad” option.
Image Source – Apple
Alternatively, you can go to your Mac’s Control Center, and select the “Screen Mirroring” button. From there, select your iPad to extend/mirror the entire Mac screen.
Since this is a built-in feature, we’d recommend users to check this out first to see if your devices/OS versions are compatible.
iPad to Windows PC Connectivity
Unlike Macs and iPads, Windows doesn’t have a native solution like Sidecar, instead, you’ll need to use a third-party app to mirror or extend your Windows PC screen to an iPad.
One of the best known options to do this is spacedesk, which is specifically designed to turn tablets and other devices into secondary displays for Windows PCs. All you need to do is install the spacedesk Driver on your PC, and the spacedesk Viewer app on your iPad.
Then, connect both devices to the same network.
From there, you can extend or mirror your Windows screen to the iPad. But if you’d prefer a wired connection, spacedesk also supports USB connections with iOS.
Plus, the added bonus of using spacedesk is that it supports touch inputs from your iPad, and emulates the command on your Windows PC. This way, the iPad isn’t just a second screen, but can be used to control, draw, or as an additional input option.
Q3: Does Sidecar work with all Mac and iPad models?
Sidecar works on most of Apple’s latest Mac and iPad models, but not all older models support the feature. Here’s a quick rundown on supported hardware models and OS required to use Sidecar:
macOS Versions: macOS Catalina 10.15 or newer
iPadOS Versions: iPadOS 13 or newer
Supported Mac models:
- MacBook Air (2018 or newer)
- iMac (Retina 5K, 27-inch, 2015)
- All Mac models released after 2016
Supported iPad models:
- All iPad Pro models
- iPad (6th Gen) or newer
- iPad Mini (5th Gen) or newer
- iPad Air (3rd Gen) or newer
Q4: Can I use multiple iPads as external monitors at the same time?
Unfortunately, no, you can usually only use one iPad as an external monitor at any time using Sidecar for Mac to iPad mirroring. However, for third party solutions like Duet Display, you can use one iPad with Sidecar, and another with Duet Display for a multi-screen setup.
Windows & Android Devices
Q1: Can I use a Windows laptop / Surface tablet as an external monitor for another PC or Mac?
Windows Laptop/Surface Tablet to Windows PC Connectivity
Yes, you can use a Windows laptop or Surface tablet as an external monitor to another Windows PC. Windows PCs have a built-in solution called Wireless Display to connect one PC and use another PC as a secondary display.
Here’s a quick guide to get started. First, you’ll need to allow the connection:
- Go to the System option in Settingson the PC you’d like to project to.
- Select Projecting to this PC.
- Next to Add an optional feature, select View features, and type “wireless display”.
- Select the checkbox for Wireless Display, click Next, and install the feature.
- After it’s installed, go back to the Projecting to this PC page.
- Type wireless display to launch the Wireless Display app.
After that, on the PC you’d like to project from, hit the Windows key + K and select the PC you’ve set up above. This is a great way to get some extra screen space, but if you’re truly looking to level up your productivity, a portable business monitor is your best bet.
However, this solution only works for Windows PCs where both laptops/tablets support Miracast and Windows 11 PCs.
Windows to Mac Connectivity
For Windows-to-Mac connections, you’ll need a third-party solution like Duet Display. Windows does not have any native solution to connect to a Mac laptop or desktop, but third-party apps allow this provided they support both Mac and Windows connections.
Q2: Can I use an Android tablet / Samsung tablet as a second monitor?
Yes, you can use Android tablets as a second monitor for Windows PCs, but again, there is no native solution for most brands. You’ll need to use third-party software like spacedesk to use an Android tablet as a second display for Windows PCs.
Image Source – Samsung
However, for supported Samsung Galaxy Tab models, you could also use the built-in Second Screen feature. This allows supported models to connect to a compatible Windows PC wirelessly and can both duplicate or extend your PC’s desktop.
Q3: Can I use my phone as a monitor for PC or Mac?
Yes, but your options are more limited than with a tablet because of the smaller screen.
For Windows PCs, spacedesk supports Android and iOS devices as secondary displays, while Duet Display supports Android and iPhone as second displays for Mac and PC.
Connection, Performance & Functional Questions
Q1: Do I need a cable, or can I connect wirelessly to use a laptop/tablet as an external monitor?
You don’t necessarily need a cable to connect your laptop or tablet as an external monitor, since most solutions are software-based. This means they typically have multiple connection options, while some only work through a network connection, such as deskreen.
However, we do recommend using a wired connection. This makes for a more stable connection especially for fast-paced workflows.
Q2: Will there be lag when using a tablet as an external monitor?
Realistically, yes, there will be at least some noticeable lag when using a tablet as an external monitor. Since this is usually achieved by a third-party solution and a wireless connection, you may notice input lag and latency.
Wired connections do perform better in general, but it still won’t match the performance of a new portable monitor, for example.
Q3: Can I use my laptop or tablet as a touchscreen monitor?
Yes and no, because it mainly depends on the software you use. Even if the device itself is a touchscreen panel, it doesn't automatically mean your PC supports touchscreen input through it.
However, some software, such as spacedesk supports touch input, so look around for options that have the feature before settling on a method.
Q4: What apps let you use a tablet as a second monitor?
Here are some of the most popular apps that let you use a tablet as a second monitor:
- spacedesk
- Luna Display
- Duet Display
- Deskreen
- AirDroid Cast
The Reverse Setup – Connect External Monitors To Your Device
Q1: Can I connect an external monitor to a MacBook / iPad?
Connecting an external monitor to a MacBook
Yes! Most modern MacBooks can connect to an external monitor using the Thunderbolt/USB-C ports, while select MacBook Pro models also include an HDMI port.
But to connect to an external monitor, you’ll need the appropriate cable or adapter for your display, so double-check your model and see what ports it has.
Connecting an external monitor to an iPad
Yes, you can connect an external monitor to an iPad, but it varies by iPad model.
Compatible iPads connect to external displays through USB-C to duplicate the screen, while newer models can not only mirror, but use a monitor as an extended workspace for your iPad.
However, to use an external monitor as a second extended workspace, you’ll need one of these supported models:
- iPad Air 5th Generation or newer
- iPad Pro 11-inch (3rd Gen or newer)
- iPad Pro 13-inch (5th Gen or newer)
But if all you’re looking for is to just mirror your iPad onto a larger display, compatibility is broader, with support even for a select iPads with Lightning cable ports. You may require specific cables/adapters.
Q2: How many external monitors can a MacBook support?
In general, MacBooks can connect between 1 – 4 external monitors simultaneously, however, it heavily depends on the MacBook model and the chip inside it.
Here’s a quick breakdown of the maximum supported external monitors for each Apple silicon model:
MacBook Air –
- M1:1 external display
- M2:1 external display
- M3: 2 external displays, but requires the lid to be closed for the second display.
- M4:2 external displays
- M5:2 external displays
MacBook Pro –
- M1/M2: 1 external display
- M1 Pro / M2 Pro / M3 Pro:2 external displays
- M1 Max:4 external displays
- M2 Max / M3 Max: 4 external displays
- M3:2 external displays, but requires the lid to be closed for the second display.
- M4 / M4 Pro / M5: 2 external displays
- M4 Max / M5 Max: 4 external displays
- M5 Pro: 3 external displays
Older Intel-based MacBook models have different display limits, so check Apple’s specifications to verify how many external displays they support. For a complete breakdown of supported resolutions, refresh rates, and display configurations, check Apple’s official external display guide.
Repurposing Old Hardware
Q1: Can I use an old laptop screen / a broken laptop as a secondary monitor?
Yes, but it depends on what still works. If the old laptop is functional, you can use one of the software mentioned above such as Duet Display or spacedesk to turn it into a second display.
But if the laptop itself is broken while the screen still works, it's a bit more complicated. Laptop displays typically don't have the same HDMI or DisplayPort inputs found on standalone monitors, which makes repurposing a laptop screen generally not worth the effort.
Closing Summary
There are plenty of ways to repurpose a MacBook, Windows laptop, tablet, or even a phone as a secondary display! While some devices offer built-in solutions like Apple’s Sidecar or Samsung’s Second Screen, third-party apps can be a great option.
Just keep in mind that performance, compatibility, and connection options vary between devices, so it’s worth checking what your hardware supports before getting started.
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