Setting Custom Resolutions for Displays in Mac OS X


Being a Mac OS X user means you are used to having a lot of stuff done for you by the system. The minimal controls you have over the system are designed to make using your machines easier. It all goes along with the Apple aesthetic and Human Interface Guidelines for clean Zen-like simplicity.

But where possible there are in fact deeper levels of control; you just don’t see them right off the bat. Setting custom display resolutions is a very good example.

In this article we’ll show you how to find the settings for custom resolutions in the Mac OS X settings, as well as some other little known facts relating to displays that you might find useful.

New Resolution

Adding a new display to your Mac in Yosemite and above means you may have to edit the display resolution in the System Preferences. Sometimes you get lucky and the system senses what your monitor is and adjusts it accordingly, or the system chooses a low-res common size so you can see what you are doing, but sometimes you have to wade in and change it manually.

This is not a problem. Just go to the “Display” section in the System Preferences app, and click on the Displays icon. The default is to accept the default maximum resolution available.


Just close the window, and you are done.

Or if you are not happy with the default, or it’s wrong for some bizarre reason, you can choose “Scaled.” A helpful range of resolutions you have available with the monitor you have attached are presented as a list; choose one to change it.

But what if your resolution isn’t on the list for some reason? Or what if you have a reason for setting a certain resolution for technical reasons?

To use a real world example, we record our Premium tutorial videos in HD, and these are screen-captured at the monitor resolution and aspect ratio on a Mac and edited and resized to HD 720p.


Often the monitor used is not in an HD aspect ratio, which means when the video is edited the height and width of the frame doesn’t fit in an HD screen, resulting in either black bars at the sides or the top and bottom.

In order to fill the screen properly we need to use the highest resolution our monitor can support but in the 16:9 ratio (we’ve discussed aspect ratios before). To get the captures we need we have to be able to set a non-standard resolution to make the aspect ratio correct. In our case this is 1680 x 944.

The settings are there, but they are actually hidden most of the time, only to be revealed when you press and hold the Option key while accessing the display preferences.

When you press and hold the “Option” key, you not only see additional available resolutions, but you also reveal the “Detect Displays” button for seeking any additional displays you’ve added since the machine was booted.


You probably won’t see the full list instantly when pressing the Option key. You may find you need to quit out of the Display Prefs and come back into them holding the Option key to see the full list of resolutions.

And don’t forget you can access the display options on other screens you are using, too, and set those independently of the main screen. Use the Detect Displays button (revealed when you press Option) to find the new displays and set their preferences.

Additional Displays

Yes, although it’s not obvious, you can also add additional displays to your Mac if it has alternative display sockets. Modern Mac Mini computers, for example, have both HDMI and Mini Port displays. These are not either/or alternatives because you can actually connect both.

Plus, if you really need additional displays, don’t forget the wonderful USB-driven displays you can get, like this one. Using USB 3.0 they can add to your existing displays and be configured to act as extensions of your existing screens, and they are actually not that expensive.


There’s a lot more to your Mac display capabilities that is not obvious at first glance. We hope you enjoyed this article, and be sure to share any questions about Mac displays in the comments below.

Image credit: FlickrFriday #33: Business as usual

Phil South
Phil South

Phil South has been writing about tech subjects for over 30 years. Starting out with Your Sinclair magazine in the 80s, and then MacUser and Computer Shopper. He's designed user interfaces for groundbreaking music software, been the technical editor on film making and visual effects books for Elsevier, and helped create the MTE YouTube Channel. He lives and works in South Wales, UK.

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