What to KnowConnect a monitor to your Mac using HDMI, Mini DisplayPort, USB-C, or Thunderbolt ports. Your Mac will automatically recognize it.If your monitor doesn't have the right input for your Mac, you will need to buy a special cable or adapter.Open the Apple menu > Displays > Arrangement, and uncheck the Mirror Displays box to use dual monitors.
This article explains how to set up dual monitors on a Mac, including how to connect a second monitor to a Mac laptop like MacBook Air and how to connect two monitors to a desktop Mac like Mac Mini.
If your Mac is running Catalina or newer and you have an iPad, you can use your iPad as a second monitor.
How to Choose a Monitor for a Mac
If you've never set up dual monitors before, finding the right monitor can seem like a daunting prospect. To choose the right monitor, you need to consider the display's size, resolution, color accuracy, and other characteristics. If you have a desktop Mac that already has a monitor, matching that monitor with another identical unit provides the smoothest experience. If you're adding a second monitor to your MacBook, you may want to consider going with a bigger 4k monitor to maximize your screen real estate or a compact flat panel display that you can take with you on the go.
It's also important to consider the type of inputs a monitor accepts, but that isn't as big a deal. If you find the ideal monitor, but it only has HDMI inputs, and you're using a MacBook that only has USB-C, all you need to do is pick up a USB-C to HDMI adapter or a USB-C hub that includes an HDMI port. You can also find adapters to go from HDMI to other outputs like Mini DisplayPort, so don't let inputs hold you back when choosing a monitor.
How to Know Your Mac Supports the Monitor You Choose
Before you settle on an additional monitor or a dual monitor setup, make sure that your Mac can handle the resolution. Most Macs can run and exceed 1080p on multiple monitors, but your Mac may not be able to take an additional 4K display. To find out exactly what your Mac can handle, you'll need to check out the technical specifications on Apple's website.
Here's how to find out what kind of monitor your Mac can handle:
Navigate to Apple's site.
Type the model and year of your Mac into the search field and hit enter.
Locate and click your Mac's listing in the search results.
Scroll down to the Video Support section, and look for the dual display and video mirroring bullet point.
In this example, you can see that a 2011 MacBook Air 11-inch can display its native resolution on the built-in display while also outputting video to an external display at a resolution of 2560 x 1600 pixels. That means this particular Mac could handle a 1080p display easily, but it wouldn't work with a 4K monitor.
How to Set Up Dual Monitors On a Mac
Once you've obtained a monitor for your MacBook or two monitors for a desktop Mac like a Mac Mini, you've verified your Mac can handle the monitors, and you have either the necessary cables and adapters, you're ready to set up dual monitors on your Mac.
Here's how to set up dual monitors on a Mac:
Connect the monitor to the Mac using the appropriate cable and adapters if necessary.
If you're setting up dual monitors on a desktop Mac, connect both monitors during this step.
Position your monitors and Mac where you want them on your desk.
Turn on your Mac. It will automatically detect and activate the second monitor, although the settings may not be to your liking.
If the monitor doesn't turn on automatically with the Mac, turn it on manually.
Click the Apple menu icon.
Click System Preferences.
On your main display, click Arrangement.
If the mirror displays box is checked, both monitors will show the same image at all times.
On your main display, make sure the mirror displays box is unchecked.
On your main display, you'll see a diagram showing the positioning of your displays. If they're not positioned correctly, locate the secondary monitor icon.
If you're satisfied with the monitor positioning, you can skip to step 12.
Click and drag the secondary monitor into the correct position.
Release your mouse or trackpad, and the secondary monitor will drop into the position you chose.
Your monitors are now ready to use, but you may need to configure the new monitor. Make sure the image doesn't look stretched, squashed, discolored, or anything. If it doesn't look right, click Scaled.
Click the correct resolution for your display.
Select the native resolution for your monitor for the best results. It needs to be equal to or lower than the resolution that your Mac is capable of handling.
If your second display looks right, you can close the display settings and start using your Mac.
The Mac mini running Apple's M1 chip can only use one Thunderbolt/USB 4 monitor at a time. If you want to add a second monitor to the M1 Mac mini, you have to use the Mac mini's HDMI port. Officially, MacBook Air and MacBook Pro models using the M1 chip only support one external monitor. The M1 MacBooks and MacBook Pro models can use one external monitor and their built-in display simultaneously.