How to Configure Screen Brightness in Ubuntu

If you are staring at the screen everyday, I am sure you will want to make the screen comfortable for your eyes. Adjusting the correct brightness is not only essential to protecting your eyes, it also helps to conserve battery power and reduce your electricity bill. In Ubuntu, adjusting the screen brightness is easy, but customizing it requires you to go deep into the settings. Let’s see how you can configure the screen brightness in Ubuntu.

Note: The brightness setting is only applicable if you are using a laptop. On a desktop, you can easily adjust the screen brightness on the monitor.

The easiest, and the most obvious way to adjust the screen brightness is via the System Settings. In the System Settings, you should see an option with the name “Brightness and Lock”.


Going into the Brightness section, you will be able to drag the slider to adjust the brightness level (assuming you are using a laptop)


You will also see an option for the system to “dim screen to save power”. Selecting this option will turn the brightness down when the system is idle (no keyboard or mouse movement).

If you feel that the brightness level in the idle mode is still too high, or that the system go into dim mode too fast/slow, here is how you can change the brightness settings.

Open a terminal and type:

Note: If it says the command is not available, you will have to install the dconf-tools package.

In the dconf-editor, on the left pane, navigate to “org -> gnome -> settings-daemon -> plugins -> power”. You should see the following image:


From here, you can change the “idle-brightness”, “idle-dim-ac”, “idle-dim-battery” and “idle-dim-time” settings. A quick explanation of the terms:

  • idle-brightness – the brightness level when the system is idle. I have set it to only 10% of the full brightness. You can set it higher or lower depending on your needs.
  • idle-dim-ac – Enabling this option will dim the screen when the system is idle and running on AC power.
  • idle-dim-battery – Enabling this option will dim the screen when the system is idle and running on battery.
  • idle-dim-time – the amount of time before the system transits into idle mode. The default is 90 seconds, but I have turned it down to 15 seconds.

The settings will take effect immediately upon changes. Once you have made the necessary changes, you can just close the dconf-editor.

If your laptop doesn’t come with a dedicated brightness control button, and you don’t like to go to the System Settings to adjust the brightness everytime, you can install the “indicator-brightness” to directly adjust the screen brightness from your desktop.

In your terminal,

Once installed, you should be able to see the brightness indicator in your system tray. Click on it to adjust the screen brightness.


If you have noticed, no matter which level you have adjusted the screen brightness to, on the next reboot, the brightness level will go back up to 100%. This is probably a bug that Canonical has not get around to solve. Here is a walk around to get the brightness level to stick.

Install xbacklight:

Open the “Startup Applications” and add a new startup item with the command:


The “40” in the above command is the level of the screen brightness, in percentage, that you want to set. You can change it to the value you want, say 60, or 80.

Save the entry. On the next restart, you should see the brightness level automatically tuned down to a lower level after you have logged in.

Note: xbacklight will only take effect after you have logged in. The brightness level at the login screen will still remain at 100%.

Adjusting the screen brightness may seem like an easy task, but apparently, there are more to it than the standard dimmer/brighter brightness control button. Hopefully, with this tutorial, you will be able to solve the brightness issue that have been bugging you from the start.

How do you manage your screen brightness in your Ubuntu?

Image credit: Light Bulb by Big Stock Photo.