Which iMac can be used as a monitor? Every model from 2009 to today

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How do I find my exact iMac model?

Open the Apple menu and choose “About This Mac”. Note the complete model name, including the screen size, the Retina designation and “Mid” or “Late” where shown, and check the macOS version installed: the newest system your model supports may differ from the one it currently runs. This matters especially for 2014 and 2015 iMacs, because models from the same year have different display options and macOS limits. Apple's guide to identifying your iMac model helps you match yours.

Which iMac can be used as a monitor, model by model?

Read the table with two separate checks in mind. “Target Display Mode” is Apple's own feature: where it's available, the iMac must run macOS High Sierra 10.13.6 or earlier, and the other Mac must meet Apple's requirements described below. “MacDisplay” shows whether the model can run macOS 11 Big Sur or later, the minimum for the Mac used as a screen; you still need that system installed and a main Mac with macOS 12.3 or later.

From 2021 on, every iMac, the 24-inch models with Apple Silicon up to the latest one released, runs the latest version of macOS and works with MacDisplay both as the screen and as the main Mac.

Sources: Apple's compatibility lists for OS X El Capitan, macOS High Sierra, Catalina, Big Sur, Monterey, Ventura, Sequoia, Tahoe and the current macOS, and Apple's Target Display Mode page. The MacDisplay column follows the macOS versions Apple supports on each model.

What else does Target Display Mode require?

A supported iMac is only half of a Target Display Mode setup. Apple also requires the other Mac to have been introduced in 2019 or earlier and to run macOS Catalina or earlier, and the feature doesn't work with Boot Camp or Windows. The 2009–2010 iMacs use a Mini DisplayPort cable, the 2011–mid 2014 iMacs a Thunderbolt or Thunderbolt 2 cable (source: Apple). In practice, a Mac with Apple Silicon can't use Target Display Mode at all, because none was introduced in 2019 or earlier: that's the gap MacDisplay fills, over its own connections.

Can I use a Late 2014 Retina 5K iMac or a 2015 iMac as a monitor?

The Late 2014 Retina 5K iMac never had Target Display Mode. The Mid 2014 21.5-inch iMac is a different model, so advice for “an iMac from 2014” isn't precise enough. A Late 2014 Retina 5K iMac running macOS 11 Big Sur meets MacDisplay's requirement for the Mac used as a screen.

For 2015, tell the Mid 2015 Retina 5K apart from the Late 2015 family: their latest Apple-supported systems differ, as the table shows, but both can reach macOS 11, MacDisplay's minimum. Check what's installed on yours before choosing the connection.

Can I use a 2017 or 2019 iMac as a second monitor?

A 2017 or 2019 iMac running macOS 11 Big Sur or later meets the requirement for the Mac used as a screen. Neither generation supports Target Display Mode, and an HDMI cable alone doesn't turn either one into a conventional external display.

Our published Clock Test used an M4 Pro MacBook Pro and a 2017 Retina 5K iMac connected over Ethernet: two photographs showed visible offsets of about 80 and 70 ms. They're two observations, not an average or a maximum for other setups; the details are in our latency test.

How do I connect an eligible iMac with MacDisplay?

Check both Macs first, including macOS 12.3 or later on the main Mac: our support page has a compatibility check for your two models.

1. Install and open MacDisplay on both MacsThe in-app guide walks you through the first-time permissions.
2. Connect the two MacsThunderbolt 3, 4 or 5, Gigabit Ethernet or 5 GHz Wi-Fi. A cable is recommended for daily use; with a Mac that has only Thunderbolt 2, use Ethernet or Wi-Fi.
3. On the iMac, choose “Become a monitor”Or press ⌘⇧M.
4. On the main Mac, choose “Extend screen”Or press ⌘⇧E, then follow the in-app guide to complete the connection.

The iMac becomes an extended second screen for the main Mac: keep a document, a browser window or reference material there while you work on the main display. For the full setup, read our guide on how to use an old iMac as a second monitor; if your main computer is a desktop, see using an iMac as a monitor for a Mac mini or Mac Studio.

Can I try my iMac before buying?

MacDisplay's free version never expires and needs no account or credit card. Extended-screen use comes in 10-minute blocks, up to 60 minutes a day on the main Mac; the iMac that receives the screen is never limited. Check your model and installed macOS, then try it with the work you usually do: it's the most practical way to decide whether the iMac you already own belongs beside your main screen. If you decide to buy, MacDisplay costs €29.99 + VAT once, with no subscription and updates included, and one license covers up to three personal Macs that extend their screen, control another Mac or send files. The Macs on the receiving end, the ones used as a screen, controlled or receiving files, need no license and have no limits, even in the free version: you can use as many as you like.

Frequently asked questions

Team MacDisplay MacDisplay Published on 21 October 2026

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