Duet turns your iPad into a second computer display


dueticonReal estate can be a wise investment — screen real estate, in particular. Two or more displays means less time switching between apps and resizing windows, and more time being productive. My desktop setup includes two 30″ monitors, plus a third 21″ monitor in portrait mode.

So when I’m traveling with my laptop, working on even its relatively generous 15″ screen feels like I’ve been taken to Willy Wonka’s television room and hopelessly shrunken to an unacceptable size. I keep yearning for that second monitor to temporarily place a document so I don’t have to endlessly shuffle things around.

I was an early adopter of the Air Display app, which used to require a Wi-Fi connection (recent updates allow a USB connection). The latency and display quirks consigned it to the list of my orphaned apps.

So when my colleague Robert Puff alerted me to Duet Display, a new app developed by engineers who used to work at Apple, I decided to give the concept another try. Duet promises a lag-free connection to your Mac or PC via your iPad’s 30-pin or Lightning cable and USB.

I bought the $16 app from the iTunes store and downloaded the free desktop companion app from the developer’s site (all Macs running 10.9+ or PCs running Windows 7+ are supported). From there, it’s just a matter of opening the Duet app on the computer to install a graphics driver, restart, and connect the two devices.

As you’d expect from ex-Apple engineers, the implementation and execution was as simple as could be, and in no time, my “real estate investment” paid off handsomely.


You’ll want to uncheck Mirror Displays in the Displays section of System Preferences, and arrange the screens to your liking.


Duet installs itself as a menu bar icon on your desktop, and you have various options to set the resolution and frame rate, which have energy implications you may wish to consider if you’re low on battery power. For my purposes, the regular resolution at 30 fps worked just fine.


An extra bonus, as I demonstrate in the video below, is that you can use the touch feature of your iPad to control the mouse pointer. To be clear, it’s still not the same as running an app with native touchscreen support — the app is, after all, still actually running on the Mac — but I must admit it was fun to see Sibelius displayed on an iPad and simply touching the screen to move around.

Duet is available for $16 from the US iTunes store; UK users can have it for £12; EU and Australian pricing is €16 and 20 AUD, respectively.



  1. Peter

    Philip, that’s a great idea with the iPad. That little stand you have the iPad sitting on, is that also a charging stand and where can I get it. I click on the video and nothing happen except the screen got larger. You said it was a video.
    Thanks for the post.

    1. Philip Rothman

      Hi Peter, here’s a link to the video if you can’t see it.
      The stand is something I bought for the iPhone 5 and basically rigged up with some extra support to handle the iPad.

  2. Gordon

    This is an excellent new facility. As I’m away from home at the moment, with laptop and iPad, I have installed he program, and it works wonderfully on ‘mirror display’. However, having unchecked ‘mirror display’, I’m stuck on what to do next, in order to feed a different image to my iPad. (Please forgive my lack of technical knowledge!)

    1. Philip Rothman

      Gordon, simply click and drag the image of the displays to arrange them so that they appear as shown in the post.

  3. Gordon

    Please can you elucidate? I deselect mirror dislay, I drag the smaller image to the right, where my iPad is positioned. I go back to the Sibelius screen, but nothing appears on my iPad screen. How do I get my iPad to actually display what I’m working on?

    1. Philip Rothman

      Gordon, I assume you have opened the Duet app on your iPad? You might try contacting Duet’s technical support if you’re having trouble.

      1. Gordon

        Thanks, Philip. Yes, of course I have opened Duet on the iPad, and then gone to system prefs on the laptop to deselect mirror display. Anyway, am following your suggestion, and trying technical support…

  4. Carole Prietto

    Cool app – Going to try this out with my iPad Pro. Enjoyed the post and enjoying the blog!

    1. Philip Rothman

      Thanks, Carole! Duet is a great way to get a second display on a mobile setup if you already have an iPad.

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