Connect an external display to your iMac
You can connect one external display (up to 6K), a projector, or an HDTV to either of the two Thunderbolt / USB 4 ports 
on the 24-inch iMac. The two USB 3 ports on the 24-inch iMac with four ports don’t support video output or an external display.
The Thunderbolt 3 (USB-C) ports on the 21.5-inch iMac and 27-inch iMac support video output. You can connect an external display, a projector, or an HDTV.
Note: If you connect multiple devices to a single port and one of the devices is an external display, the display must be the last device in the connection.
To connect this device to a Thunderbolt / USB 4 or Thunderbolt 3 (USB-C) port | Use this cable or adapter |
|---|---|
Apple Pro Display XDR (24-inch iMac only) | Thunderbolt 3 (USB-C) cable |
Thunderbolt 3 (USB-C) display | Thunderbolt 3 (USB-C) cable |
USB-C display | USB-C (USB 3.1) cable |
Thunderbolt 2 display | Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter |
HDMI display or HDTV | USB-C to HDMI adapter or a USB-C Digital AV Multiport adapter |
VGA display or projector | USB-C VGA Multiport adapter |
DisplayPort or Mini DisplayPort display | USB-C to DisplayPort or Mini DisplayPort adapter |
DVI display or projector | USB-C to DVI adapter |
If you have an HDTV connected to an Apple TV, you can use AirPlay to mirror your iMac screen in up to 1080p HD. See Use AirPlay on your Mac for details.
Adapters and other accessories are sold separately. Visit apple.com, your local Apple Store, or other resellers for more information and availability. Review the documentation or check with the manufacturer to make sure you choose the right product. See Adapters for the ports on your Mac or iPad Pro.
Learn more. See the Apple Support article Use external monitors with your Mac for details about extending the desktop, video mirroring, and other display preferences. To troubleshoot an issue with an external display, see Get help with video issues on external displays connected to your Mac.