AirPlay Display Is the macOS Feature You Didn’t Know You Needed

It can turn your Mac or iPad into a second monitor with ease

Key Takeaways

  • AirDisplay turns another Mac or an iPad into a display for your Mac.
  • It replaces the long-dead and still-loved target display mode.
  • You can use it via Wi-Fi or USB.
An iMac and MacBook computer connected as a single, dual screen machine.

Devon Janse van Rensburg / Unsplash

If you ever wanted to use an old Mac as a dumb monitor for your new MacBook, AirPlay Display is for you. 

In the past, target display mode let you repurpose an iMac as an external display for another Mac. That feature withered and only works on older devices, but Apple has resurrected the concept with AirPlay Display. With AirPlay Display, you can co-opt any nearby Mac or iPad screen and use it as a second or main display. The feature is both amazingly useful and a bit frustrating.

“Target Display Mode was a system function in macOS that allowed an iMac to serve as a display for another Mac. It still works with Thunderbolt on pre-retina iMacs,” Jonathan Tian, Co-Founder of smartphone data transfer service Mobitrix told Lifewire via email. 

AirPlay Display

AirPlay Display is like magic. You open up the display preferences on your Mac, just like you would if you're connected to a regular external monitor. At the bottom left of the window is a drop-down menu to 'Add Display.' Clicking that shows a list of available Macs and iPads.

You can then add these displays and choose whether to use them as a mirror, show your same Mac desktop—only bigger—or extend the display, adding a second monitor to show different apps. 

Apple has offered similar functionality in the past, but in macOS Monterey, it's a proper grown-up feature. You can even arrange the display layout and change the resolution. 

A screenshot of the Displays dialog box when setting up AirPlay Display with another device.

Once up and running, the target Mac just acts like a regular external display. If you do it over Wi-Fi, there's a slight delay. If you can't live with that, you can use a USB-C cable. 

What Can You Do With It?

So, you now have two displays. What can you do with them? The short answer is: Anything you like. It’s just another display connected to your Mac. But how about some useful examples?

One handy use is to shift communication apps off to your iPad’s screen. Anything you may glance at is a perfect candidate: Twitter, iMessage, or a newsreader app.

“Using my iPad as a second screen through AirPlay Display is a life-changing experience,” says software developer Jamshid Hashimi on Twitter

Another use is to mirror your MacBook’s display to the bigger iMac. Why not just use the iMac instead? That’s a good question! The best answer may be that it’s somebody else’s iMac. Perhaps you are a guest in somebody’s home, and you want to use their big screen to get some work done. 

Unfortunately, this brings us to AirPlay Display’s biggest frustration. To use it, all the machines involved have to be signed in to the same Apple ID, which means your Apple ID. One workaround would be to have your friend create a user account for you on their big iMac, and then you could log in to your iCloud account. But that’s a lot of hassle, and you’d have to trust that friend to type your Apple ID into their computer. 

Screenshot of the monitor arrangement dialog box in Displays on a Mac.

One wonders why this requirement couldn’t be bypassed for a connection with a wire. 

So far, AirPlay Display might seem like a bit of a gimmick, but here are two ideas that might change your mind. One is to use an iPad as a second display for a MacBook. If it’s a big 12.9-inch iPad Pro, you can connect them with a single USB-C cable and effectively double your available screen area. It’s a pretty compelling use case. 

The other is to effectively give yourself a touch-screen Mac. For example, you could put a window from the Ableton Live music-creation app onto an iPad and use it with the Apple Pencil. I tried this, and it works incredibly well, even over Wi-Fi. 

The Future

This is going to sound absurd, but until Apple ships a standalone monitor that’s cheaper than the $5,000 Pro Display XDR, the best display for your MacBook Air or Pro might be an iMac via AirPlay Display. The most affordable model is $1,299, which is expensive but not crazy for a good display panel, plus it comes with a computer attached. 

And on the other end of the wastefulness spectrum, being able to repurpose most Macs and iPads you already own is a sustainability win. It’s not perfect, but AirPlay Display is pretty great.

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