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How to Set Up External and Dual Monitors on a Mac

Authored by:
Support.com Tech Pro Team
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Introduction

When you work with a lot of documents at once, or find yourself with a lot of windows open, it can become welcome, if not necessary, to have more display room for your work all at once on your computer. Rather than buy a single, larger monitor, you can use a second one to display either the same or different windows.

This guide will take you through the basics of setting up a second monitor for your computer.

Dual Monitors

1 Set Up the Work Space for Dual Monitors

Our first step is to be sure we have all the necessary physical hardware available and a space to put it.

On Your Desk
A multiple monitor set up for a Mac

  • Make sure there's enough space for both monitors to fit on the desk where you don't knock against them.
  • Make sure you can still reach your keyboard and mouse comfortably.
  • Make sure you can see both monitors when you sit down and make sure viewing the two monitors does not hurt your neck.

For Each Monitor on Your Desk

  • Each monitor needs a power cable or adapter, and an outlet to plug it in. The outlet could be on a power strip or power protector.
    Arrows pointing a power cable to monitor and outlet
  • A video cable such to connect to your Mac that fits one of the ports on your monitor. This will either be a thunderbolt cable or a mini-display port. You may need an adapter for this.

    Desktop
    Video cable plugged into monitor and computer
    Laptop
    Video cable plugged into monitor and laptop

For Your Mac to Connect to a Monitor

  • You need a port for each monitor. Macs have Thunderbolt connectors and mini-display ports. You may need an adapter for this.
    The back of a Mac
  • The ports on your computer must match the cables coming from both your monitors. Do not force the cable connectors as they should slide in easily.
For macBooks where you intend to use the built-in display as one of your monitors, you only need one place to plug in the second monitor on the macBook.
Adding another monitor adds, at minimum, two more cables to your computer setup. Please be sure these cables will not be caught or snagged by your chair, desk, or people walking by.

2 Connect the Additional Monitor

Now that you know you have all your cords, cables, and desk space, let's connect the second monitor to your Mac.
  1. Connect the video cable to your monitor.
    Monitor with the cable plugged in
  2. Connect the other end of the video cable to your computer.
    Mac with a mini display port connected
  3. Connect power to your new monitor:
    1. One connector (1) plugs into the monitor.
    2. The other connector (2) plugs into a power socket.
    3. And sometimes, a third (3) connector plugs into the supply itself.
    Monitor power supply connectors annotated.
  4. Turn on your monitor.
    Power button on monitor highlighted.
  5. Turn on your computer.
    Power.

3 Manage Settings for Mac Monitors

Now that you've got everything set up, turned on, and working properly, you can adjust the settings to make it perfect for you. If you want to just mirror a smaller monitor on a larger one, you can do that. If you want to extend the display to add more space, you can do that too!

Let's open the display settings and take a look around.

Access Display Settings

  1. Click on the Apple menu and click System Preferences.
    Apple Menu with System Preferences highlighted
  2. Click on Displays.
    System Preferences with Displays highlighted
Now that we've got the display settings open, let's look at extending or mirroring your desktop.

Extended Display

You can maximize your workspace with extended desktop mode, which lets you enjoy full-screen apps and windows on each monitor.

  1. Click on the Arrangement tab.
    Arrangement tab highlighted
  2. Make sure that Mirror Displays is unchecked.
    Mirror displays highlighted
  3. You can position your monitors by dragging the monitor to rearrange how they show up.
    Monitors with arrows going left and right.

Mirrored Display

With video mirroring, all of your displays will show the same apps and windows.

  1. Click the Arrangement tab.
    Arrangement tab highlighted
  2. Make sure Mirror Displays is checked.
    Mirror Displays box highlighted

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When you work with a lot of documents at once, or find yourself with a lot of windows open, it can become welcome, if not necessary, to have more display room for your work all at once on your computer. Rather than buy a single, larger monitor, you can use a second one to display either the same or different windows.

This guide will take you through the basics of setting up a second monitor for your computer.

Dual Monitors
Our first step is to be sure we have all the necessary physical hardware available and a space to put it.

On Your Desk
A multiple monitor set up for a Mac

  • Make sure there's enough space for both monitors to fit on the desk where you don't knock against them.
  • Make sure you can still reach your keyboard and mouse comfortably.
  • Make sure you can see both monitors when you sit down and make sure viewing the two monitors does not hurt your neck.

For Each Monitor on Your Desk

  • Each monitor needs a power cable or adapter, and an outlet to plug it in. The outlet could be on a power strip or power protector.
    Arrows pointing a power cable to monitor and outlet
  • A video cable such to connect to your Mac that fits one of the ports on your monitor. This will either be a thunderbolt cable or a mini-display port. You may need an adapter for this.

    Desktop
    Video cable plugged into monitor and computer
    Laptop
    Video cable plugged into monitor and laptop

For Your Mac to Connect to a Monitor

  • You need a port for each monitor. Macs have Thunderbolt connectors and mini-display ports. You may need an adapter for this.
    The back of a Mac
  • The ports on your computer must match the cables coming from both your monitors. Do not force the cable connectors as they should slide in easily.
For macBooks where you intend to use the built-in display as one of your monitors, you only need one place to plug in the second monitor on the macBook.
Adding another monitor adds, at minimum, two more cables to your computer setup. Please be sure these cables will not be caught or snagged by your chair, desk, or people walking by.
Now that you know you have all your cords, cables, and desk space, let's connect the second monitor to your Mac.
  1. Connect the video cable to your monitor.
    Monitor with the cable plugged in
  2. Connect the other end of the video cable to your computer.
    Mac with a mini display port connected
  3. Connect power to your new monitor:
    1. One connector (1) plugs into the monitor.
    2. The other connector (2) plugs into a power socket.
    3. And sometimes, a third (3) connector plugs into the supply itself.
    Monitor power supply connectors annotated.
  4. Turn on your monitor.
    Power button on monitor highlighted.
  5. Turn on your computer.
    Power.

Now that you've got everything set up, turned on, and working properly, you can adjust the settings to make it perfect for you. If you want to just mirror a smaller monitor on a larger one, you can do that. If you want to extend the display to add more space, you can do that too!

Let's open the display settings and take a look around.

Access Display Settings

  1. Click on the Apple menu and click System Preferences.
    Apple Menu with System Preferences highlighted
  2. Click on Displays.
    System Preferences with Displays highlighted
Now that we've got the display settings open, let's look at extending or mirroring your desktop.

Extended Display

You can maximize your workspace with extended desktop mode, which lets you enjoy full-screen apps and windows on each monitor.

  1. Click on the Arrangement tab.
    Arrangement tab highlighted
  2. Make sure that Mirror Displays is unchecked.
    Mirror displays highlighted
  3. You can position your monitors by dragging the monitor to rearrange how they show up.
    Monitors with arrows going left and right.

Mirrored Display

With video mirroring, all of your displays will show the same apps and windows.

  1. Click the Arrangement tab.
    Arrangement tab highlighted
  2. Make sure Mirror Displays is checked.
    Mirror Displays box highlighted