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I have a MBP with a secondary display. Is is possible to have the brightness keys (F1 & F2) change both the main display (laptop screen) and the secondary display (a VGA external monitor connected via a Thunderbolt port with an adapter)? If not, is it possible to change the brightness on the secondary display?

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What is the brand and model of the external display, and what is the means of connection? (VGA, Thunderbolt, DVI, Mini DisplayPort). It is always helpful to give full specifications when you ask a question. – user9290 Apr 15 '12 at 1:25
@WheatWilliams Thanks! I edited my question – daviesgeek Apr 15 '12 at 5:59
I'm looking to solve the same problem but with a Mini DisplayPort monitor. For more on this topic check out:… Not surprised that Apple doesn't give a damn about standards. – Erika Jan 14 '13 at 8:52
Please change the correct answer to the one with the most upvotes so that people are sure to see it. Thanks! – nilbus Jun 6 '13 at 2:40
Use my own fork of Brightness Menulet, it supports auto adjustment based on the ambient light sensor – Muhammad Hewedy Jul 19 '15 at 20:09

17 Answers 17

up vote 33 down vote accepted

One of my favorite tools for doing this is Shades which is "donationware."

You can adjust each monitor separately, and set keyboard shortcuts for them as well.

If you want a command line solution, I found brightness.c which compiled cleanly using:

gcc -std=c99 -o brightness brightness.c -framework IOKit -framework ApplicationServices

(You'll need Xcode to be installed to compile it. If you want a precompiled version, mine is available here )

It will let you set the brightness for either monitor.

UPDATE: Note that this answer is several years old. The link above is now 404 but there is a newer tool available at or `brew install screenbrightness`
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Fixed (again). Sorry. – TJ Luoma Sep 12 '13 at 16:42
Thanks for the fixed link. It only works for my laptop display on my setup under 10.8, though. When I try to set the external it says "failed to set brightness of display 0x4246511 (error -536870201)" – Joshua Goldberg Sep 13 '13 at 1:14
+1 for Shades, it's great! – Saphrosit Oct 24 '13 at 16:25
Dead link to your precompiled version. – Daniel Pendergast Apr 28 '15 at 2:25
I was able to compile brightness.c just fine, and it works on the built in monitor. Like @JoshuaGoldberg, it errs out when the external display is connected. – senorsmile Oct 13 '15 at 1:14

If you press Control-F1 or Control-F2 the brightness on a secondary display will adjust. I have tested this on my MacBook Air 2011 13" and 27" Thunderbolt Display.

Important notes: You have to plug in the USB cable from the Display to the Macbook Pro in order that the keyboard shortcuts work. This only works on Apple Displays.

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I don't have a Thunderbolt Display. I have a standard VGA monitor, but I will try it. – daviesgeek Oct 20 '11 at 2:38
On my Mac Pro (with two DVI displays), 10.7.4, this does not work. – Ken Oct 11 '12 at 20:46
This works for my MacBook Pro with dual Thunderbolt displays. – hairboat Oct 19 '12 at 15:30
This doesn't work with displays other than Apple's I think. – Enrico Susatyo Feb 18 '13 at 23:45
This should be the accepted solution!!!! – Marcello de Sales Jan 26 '15 at 23:43

If you press CTRL and F1/F2 the brightness on a secondary display will adjust. Tested and works on my MacBook Pro (Early 2011) 15" and 27" Thunderbolt Display.

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Thanks, but I don't have a Thunderbolt display. I have a standard VGA monitor. – daviesgeek Apr 14 '12 at 22:37

Unfortunately, Macs don't have access to an external display's brightness settings. On most displays, that is only controllable using the physical buttons/menus on the display itself.

I agree that this would be a great feature to see, but it isn't really possible now to control brightness over the video cable.

Note that I can't speak for Apple's Cinema Display and Thunderbolt; I haven't tried that and it may be different.

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Yeah, I'm talking about a standard VGA monitor. Thanks! – daviesgeek Aug 5 '11 at 17:10

If you're using an Apple Cinema Display it is possible to control brightness as long as you connect the display's USB cable to your Mac. The causes a "Brightness" slider to appear on the screen's control panel in "Displays" System Preferences. Unfortunately the F1 and F2 don't change the brightness settings on the external screen.

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USB cable did it! Thanks – joet3ch Oct 10 '12 at 21:51
Macbook Pro ( 2015 ) with external 24" Cinema display only uses control F1 / F2 if the USB is connected. Just having the thunderbolt connection is not enough to get the F1/F2 to work. – RussellAlbin Jun 28 at 20:24

Another option is Brightness Slider, free in App store.

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seems to set the same brightness to all screens – ina May 26 '14 at 2:49
Wow, it works like a charm even for the macos with damaged discrete gfx card, when you can not change the brightness with the standard keys, – Skarab Jan 28 '15 at 17:29
As of today it only controls the brightness of the main monitor. I think Ina's issue was reported as a bug and maybe they "fixed" it. To me, setting all the screens to the same brightness is the correct behavior. – Craig Jacobs May 3 at 19:35

If you have an Apple Cinema display and are adjusting brightness via the "displays" preference pane, note that the preference pane will show up both on your main display (the cinema display) and on the MBP. It allows you to set the brightness separately.

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Screen Dimmer isn't free ($2), but is the only tool I could find that handles multiple monitors (up to 3).

Seems nice and elegant the short time I've used it. Sits in menubar, and has a simple slider and monitor selector, as well as keybindings for brightness increase/decrease.

My 3 external displays are non-apple (1 Dell with displayport, 1 samsung with displayport->dvi, and 1 old acer 19" with hdmi->dvi) on a MacBook Pro Retina 15" with 10.8.2.

edit: For the OP's question this shouldn't matter, but fyi for 3 monitors - it seems to only allow one combination of monitors for dimming (i.e. can't dim completely separately -- this works for me as I use it to dim the 2 side monitors so they don't distract from the main middle monitor)

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I have two screens connected to my Mac Pro. (This also works for MacBook Pro.) I have the USB on the first screen connected to the Mac. The second screen has its USB connected into the back of the first screen (the 2nd screen display adapter uses an extender to get to the Mac - you could likewise use a USB extender to get to the back of the Mac).

With both screens communicating to the Mac via screen as well as USB, F1 and F2 as brightness control the dimming of the first display, Ctrl+F1 and Ctrl+F2 control the second screen. No need to disconnect at all.

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I have 2 thunderbolt displays connected to my MBP. I had to connect only one display at a time in order to adjust the brightness. Then I reconnected them both and all was well. Too bad the control panel doesn't show the brightness slider on both displays but this is a simple solution.

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There are many answers here, but one wasn't mentioned (though it only has limited applicability---you need to have a second keyboard handy.) When I have a second display hooked up to my MBP, and a second keyboard plugged in, then the built-in laptop keyboard's function keys control the built-in (main) laptop LCD and the external keyboard's function keys work for the secondary.

In case it's changed, this is on 10.6.8.

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This has worked for me for the last couple OSX versions (Mavericks, Yosemite). – ericsoco Nov 9 '15 at 16:56

I have MBP early 2011 connected to LED display and Thunderbolt display and I use the thunderbolt display as extended desktop.

This is how you can adjust the brightness on second display.

  1. Press cmd+F1. This will mirror the displays.
  2. Press F1 or F2 and both screens will increase or decrease in brightness.
  3. When you are done, press cmd+F1 and your screens will revert back to extended desktop mode.

Ok, its a pain if you are like me and have items configured on both screens but I found using "shades" the second monitor was always looking dimmer and not the same brightness as the primary screen.

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Open System Preferences; Click Displays; In the lower left hand menu, click the Show displays in menu bar; Once your menu bar has the little icon of your monitor, click it and select Open Display Preferences;

All monitors will have a Preferences menu linked to that specific object.

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If you are using a 24" thunderbolt display which has a USB cable in addition to the thunderbolt cable, YOU HAVE TO HAVE BOTH PLUGGED IN. Then Ctrl + F1 and Ctrl + F2 should work.

I was in the middle of installing Brighness Slider when my colleague told me of this.

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A dead-simple program called Brightness Control has been dimming multiple external monitors for me since 2006. Still working fine on OS X 10.11 in 2016.


Only drawback is that you cannot simultaneously run f.lux. If you only have one external monitor, you can use Shady to dim that without quitting f.lux.

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Shady seems to only dim one display on OS X 10.11 (if you connect your monitor after Shady is already running, it will dim your main display which doesn't solve the problem). Restarting Shady after connecting an external monitor seems to force it to change the brightness on the secondary display. – victor Jul 7 at 23:01
My habits have changed some. I now dim my built-in display with the keyboard controls (I’ve come to prefer turning down the backlight vs. a semi-transparent overlay), and for my external displays I use a different ancient program called ScreenShade. Fair warning, the original host site has been taken over by malware people so don’t let it open their tutorial on the web. I like ScreenShade for monitor selection flexibility and the keyboard shortcuts (option-plus and option-minus). – duozmo Jul 7 at 23:19
Thanks for the update. Just installed, works great! – victor Jul 7 at 23:25
There seems to be a problem with CTRL+<left/right arrow> to switch between Spaces on the main display while using ScreenShade. – victor Jul 7 at 23:31
@victor Hmm, bizarre. I haven’t had that problem. I’d say double check your keyboard shortcuts in OS X Settings > Keyboard > Shortcuts > Mission Control. Otherwise, no idea... the app is from 2008 so no surprise it’s a little janky. – duozmo Jul 7 at 23:38

If you run Windows Vista, Windows 7, or Windows 8, you can adjust brightness easily with Mac Brightness Control utility.

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Yes, but does it allow you to change the secondary display's brightness? – daviesgeek Jul 21 '12 at 6:42

After experimenting with lots of hot keys I found a solution. I am using a dual screen setup with 27 inch iMac which is connected to a 27 inch Thunderbolt screen.

Using cmd+ F1 will duplicate the screen brightness of screen 1 to screen 2.

Now you can dim the 2nd screen with F1

Repeat the cmd+ F1 and the 2nd screen will revert to last brightness. Now you can dim the iMac screen with the brightness keys.

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Didn't work for me... – Mazyod Nov 16 '13 at 20:20
Cmd+F1 mirrors the whole display, not just the brightness. – thSoft Dec 3 '13 at 15:23

protected by bmike May 5 '14 at 22:07

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