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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
    Commented Apr 15, 2012 at 1:25
  • I'm looking to solve the same problem but with a Mini DisplayPort monitor. For more on this topic check out: apple.stackexchange.com/questions/61045/… Not surprised that Apple doesn't give a damn about standards.
    – Erika
    Commented Jan 14, 2013 at 8:52
  • Please change the correct answer to the one with the most upvotes so that people are sure to see it. Thanks!
    – Edward Anderson
    Commented Jun 6, 2013 at 2:40
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    Use my own fork of Brightness Menulet, it supports auto adjustment based on the ambient light sensor github.com/MuhammadHewedy/BrightnessMenulet
    – Muhammad Hewedy
    Commented Jul 19, 2015 at 20:09

21 Answers 21

Reset to default
67

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

It will let you set the brightness for either monitor.

Another tool available at: Command-line display brightness control for macOS or just brew install screenbrightness.

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  • Fixed (again). Sorry.
    – TJ Luoma
    Commented Sep 12, 2013 at 16:42
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    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
    Commented Sep 13, 2013 at 1:14
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    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
    Commented Oct 13, 2015 at 1:14
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    Note that this answer is 4 years old. There is a newer tool available at github.com/nriley/brightness or brew install screenbrightness
    – TJ Luoma
    Commented Oct 14, 2015 at 13:21
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    The formula name is even shorter now: $ brew install brightness.
    – Alex
    Commented Jul 2, 2021 at 22:03
157

On Apple displays, 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 note: You have to plug in the USB cable from the Display to the Macbook Pro in order that the keyboard shortcuts work.

If you're using a MacBook with Touch Bar, this works for the "brighter"/"less bright" Touch Bar buttons but NOT for the Touch Bar brightness slider.

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    I don't have a Thunderbolt Display. I have a standard VGA monitor, but I will try it.
    – daviesgeek
    Commented Oct 20, 2011 at 2:38
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    On my Mac Pro (with two DVI displays), 10.7.4, this does not work.
    – Ken
    Commented Oct 11, 2012 at 20:46
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    This works for my MacBook Pro with dual Thunderbolt displays.
    – hairboat
    Commented Oct 19, 2012 at 15:30
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    This doesn't work with displays other than Apple's I think.
    – Enrico Susatyo
    Commented Feb 18, 2013 at 23:45
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    All this did for me was select the apple icon in the top left of the monitor.
    – user1380540
    Commented Apr 20, 2017 at 13:58
115

Lunar is an app which allows you to automatically sync the system display brightness with the brightness of an external monitor.

With Lunar, you can use the standard display controls (and keyboard keys!) to adjust the brightness simultaneously on the main and external display, which is exactly what I wanted. It also supports tweaking of brightness and contrast ranges/offsets to get exactly the desired levels.

Lunar is not restricted to any specific display type or connection method, so it should work with most displays connected over USB-C, Thunberbolt, etc.

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    can't believe no one upvoted this answer lol the only answer worked for me. thank you thank you thank you!
    – Ezeewei
    Commented Jun 19, 2019 at 22:48
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    Of all the solutions here, this seems to be the only option that supports adjusting the brightness of the built-in MacBook display and an external non-Apple monitor simultaneously.
    – Igor
    Commented Sep 17, 2019 at 16:55
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    Lunar is now found at: lunar.fyi
    – Paul
    Commented Sep 30, 2019 at 1:07
  • Perfect solution as it can also sync with the brightness level of your Mac and is easy to use and open source.
    – PeYoTlL
    Commented Oct 25, 2019 at 3:26
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    And the best part is that it changes the native brightness of the monitor settings. The monitor settings also show the change of brightness as reported by Lunar.
    – The_Lucifer
    Commented Jan 13, 2020 at 15:19
59

Knowing that this question is rather old I want to make you aware of https://github.com/the0neyouseek/MonitorControl which is open source, well maintained and quite handy.

enter image description here enter image description here enter image description here

You can control brightness, contrast or volume directly from a menulet or with keyboard native keys. Keyboard keys even display the native osd.

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  • If you have two external monitors they can't be independently setup
    – Sebastian Sastre
    Commented Mar 16, 2020 at 11:56
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    This is the only answer that worked for my LG Ultrafine monitor. Thanks!
    – JcMaco
    Commented Mar 23, 2020 at 6:36
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    Clean and simple! Love it!
    – Paul-Sebastian Manole
    Commented Oct 12, 2020 at 12:15
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    This is the real answer everyone!!!!!!
    – sv_jan5
    Commented May 16, 2022 at 9:56
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    The newest version (v4.1 at this time of writing) even uses the system standard controls (e.g. TouchBar in my case) and synchronises brightness with the native display as Lunar is reported to do!
    – RobM
    Commented Sep 5, 2022 at 9:52
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Another option is Brightness Slider, free in App store.

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    seems to set the same brightness to all screens
    – ina
    Commented May 26, 2014 at 2:49
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    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
    Commented Jan 28, 2015 at 17:29
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    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
    Commented May 3, 2016 at 19:35
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    Beautiful little app — does exactly what I need it to. Done.
    – scottperezfox
    Commented Apr 23, 2019 at 17:40
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    Like ina said, Brightness Slider only dims the main display. There's an app called Quickshade that dims all displays like Brightness Slider, just better IMO
    – travisjayday
    Commented Jul 15, 2020 at 1:39
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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
    Commented Aug 5, 2011 at 17:10
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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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  • 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
    Commented Jun 28, 2016 at 20:24
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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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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.

Brightness Control.app

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.
    – victorlin
    Commented Jul 7, 2016 at 23:01
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    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
    Commented Jul 7, 2016 at 23:19
  • There seems to be a problem with CTRL+<left/right arrow> to switch between Spaces on the main display while using ScreenShade.
    – victorlin
    Commented Jul 7, 2016 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
    Commented Jul 7, 2016 at 23:38
  • Toggled the "Move left a space" hotkey and restarted ScreenShade, works fine now.
    – victorlin
    Commented Jul 7, 2016 at 23:47
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You can use https://github.com/kfix/ddcctl - works for my Dell P2715Q And even better there is https://github.com/czarny/Brisync which even syncs brightness with your internal display

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  • Brisync is perfect for situations where your screen is close to a window or when the difference between sunny or overcast weather can really affect readability. Thanks! 👍
    – Bart Verkoeijen
    Commented Feb 12, 2020 at 7:05
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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)

edit2: The website appears to be down so here is the App Store link. Also of note it allows for dimming up to 3 monitors but remember your MacBook does count as 1 if it's open. If you have 3 externals this means you can't dim the far right one. But, you can just close your MacBook and then you can dim all 3 externals.

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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 tried most of the other suggested solutions. On the latest High Sierra with a non-Apple external display over usb-C these suggestions didn't work. I did stumble upon an app called EasyOnTheEyes that actually does the trick. https://itunes.apple.com/ca/app/easyontheeyes/id799584781?mt=12 . It hasn't been updated in a while, but still seems to work.

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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
    Commented Nov 9, 2015 at 16:56
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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.

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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 (mirror displays) will also 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
    Commented Nov 16, 2013 at 20:20
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    Cmd+F1 mirrors the whole display, not just the brightness.
    – thSoft
    Commented Dec 3, 2013 at 15:23
  • Yeah, it does mirror whole display, but this fixes some weird bug, when you're gaming in a fullscreen mode, sometimes your 2nd screen would have very low brightness, this trick fixes it.
    – Alexander Kim
    Commented Jan 23, 2021 at 12:42
1

You can use MonitorControl Lite to install a widget that lets you do this.MonitorControl Lite controlling 2 of my monitors

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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
    Commented Jul 21, 2012 at 6:42

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