How many monitors can I plug into my Mac, anyway?

One of the Mac’s greatest long-term advantages has been the ease of attaching external monitors. The attachment connector type, resolutions supported, and total quantity has varied over time, but it’s a persistently easy task.

Or at least it was! Over the last six years, Apple introduced USB 3 over USB-C (12-inch MacBook, now discontinued), Thunderbolt 3, which uses USB-C (and supports many kinds of adapters), and the Apple silicon M1 processor models. Some Macs have or still include video-specific connectors, too: in the past, that included DVI (multiple forms), Mini DisplayLink, DisplayLink over Thunderbolt 2, and HDMI. More recently HDMI 2.0 is the only remaining video connector that’s not USB-C, and it’s found only on Intel and M1 Mac mini models.

Figuring out how many monitors can plug into which Macs has become akin to calculus for many readers, based on our mailbag.

(Have a monitor that uses DVI, Mini DisplayPort, or Thunderbolt 2? Consult our guide from last year on how to determine what you have and which kind of adapter you need. Want to use an iMac as an external monitor? Only iMacs released from 2009 to mid-2014 qualify. See “Troubleshooting tips for using an old iMac as an external display for a Thunderbolt 3 Mac.”)

Here’s the matchup for Macs of the last few generations, starting with the newest, not including the internal display for iMac and Mac laptops. Connections are via a USB-C connection except where noted.

The resolutions, for reference, are:

• 4K UHD: 3840×2160 pixels
• 4K: 4096 wide, with common variations that include 4096×2160 or 4096×2304 pixels
• 5K: 5120×2880 pixels
• 6K: 6016×3384 pixels

The highest resolution supported is listed for each configuration or set of options, but you can use a lower-resolution monitor, too. For instance, the M1 Mac mini allows up to 6K over USB-C, but you can plug a 4K UHD monitor into that port instead.

M1 Mac monitor options

Most M1 Macs allow adding only a single external monitor; the Mac mini allows two. Despite many reader questions, there’s no adapter or trickery you can do to add an additional display beyond the level Apple supports. The video circuitry simply isn’t there.

Here are your options grouped by display choices:

• MacBook Air, 13-inch MacBook Pro, iMac: One external display at up to 6K resolution
• Mac mini: Two displays: one at up to 6K over USB-C and one at up to 4K over HDMI 2.0

Intel Mac with USB 3/Thunderbolt 3 monitor options

Intel Macs with Thunderbolt 3 had a more baroque array of potential external monitor configurations. Here are the possibilities for the last shipped version of each Thunderbolt 3 model and the 12-inch MacBook with USB 3 over USB-C:

• 21.5-inch iMac: One 5K display or two 4K UHD or 4K displays
• 27-inch iMac (standard video card), 13-inch MacBook Pro: Either one 5K or 6K display or two 4K UHD or 4K displays
• 27-inch iMac (AMD Radeon Pro 5700 or AMD Radeon Pro 5700 XT): Up to two 4K UHD, 4K, 5K, or 6K displays
• 16-inch MacBook Pro: Up to two 5K or 6K display or up to four 4K UHD or 4K displays
• Mac mini: One 5K display via USB-C or up to three 4K displays with a combination of USB-C and HDMI 2.0 ports
• Mac Pro: Depending on the video card, it ranges from one 5K or 6K display or up to four 4K displays through up to four 5K or 6K displays or up to eight 4K displays
• 12-inch MacBook: One 4K display

Ask Mac 911

We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.com including screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.