I work on a laptop computer that is located near a window. As the amount of sunlight changes throughout the day, I find it necessary to adjust my display brightness regularly several times a day.
Windows doesn’t offer a direct way to adjust display brightness hour by hour. So I use the following workaround that’s just as good.
You can access your power schemes via
Or, more easily, by clicking on the
And then by clicking on
As you will see, there are three standard power schemes used in Windows — High performance, Balanced, and Power saver.
You can personalize all three to fit your needs. In this case, I personalized the display brightness settings of all three power schemes.
Personalize Display Brightness
To do this, in the Power Options window click
Then, in the Edit Plan Settings window, click
Next, find the
I made the following settings: 30% brightness for the High performance power scheme, 20% for Balanced, and 0% for Power saver.
I always set the same percentages for both On battery and Plugged in.
These settings work great for me. My 17″ Dell XPS laptop has an excellent display. The outside light is well-matched by the 30% brightness setting during the day. In the afternoon I switch to 20% display brightness, and late at night I use 0% brightness for watching movies (but not for work).
You need to find out what percentages work best for your specific lighting conditions and computer screens.
The powercfg Command
Now that you know what display brightness you wish to use, let’s summarize all the power scheme information available.
For this, we use the great
Launch Command Prompt from
This command lists all available power schemes including their GUIDs — globally unique identifiers.
Note: You can copy-paste commands to the Command Prompt’s window. However, when pasting them, you have to right-click with your mouse within the Command Prompt window and select Paste from the drop-down menu.
Here is the output list of my power schemes:
Existing Power Schemes (* Active)
Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced) *
Power Scheme GUID: 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c (High performance)
Power Scheme GUID: a1841308-3541-4fab-bc81-f71556f20b4a (Power saver)
We will be using the GUIDs. We need to print them into a file, so that we can easily copy-paste them later:
powercfg -list >> D:\Downloads\ExistingPowerSchemes.txt
Please, customize the location and name of the output text file as you see fit.
We will also be needing the Display and Display brightness GUIDs. So we need to print those into the file, too:
powercfg -query >> D:\Downloads\ExistingPowerSchemes.txt
You don’t need to create a second text file. The new output won’t overwrite the previous data. It will be added after the existing data.
Now, open up the text file and find the
Subgroup GUID: 7516b95f-f776-4464-8c53-06167f40cc99 (Display)
Next, find the
Power Setting GUID: aded5e82-b909-4619-9949-f5d71dac0bcb (Display brightness)
The Display and Display brightness GUIDs are the same across all Power Schemes.
Putting the GUIDs to Use
Now we will create three commands, one for each power scheme, using all the above-mentioned GUIDs. Here is the command scheme:
powercfg -setacvalueindex PowerSchemeGUID DisplaySubgroupGUID DisplayBrightnessSettingGUID Percentage
In my case, the three commands created looked as follows.
Morning brightness — High performace power scheme:
powercfg -setacvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 30%
Afternoon brightness — Balanced power scheme:
powercfg -setacvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 20%
Night-Time brightness — Power saver power scheme:
powercfg -setacvalueindex a1841308-3541-4fab-bc81-f71556f20b4a 7516b95f-f776-4464-8c53-06167f40cc99 aded5e82-b909-4619-9949-f5d71dac0bcb 0%
You can set the display brightness manually via Command Prompt using the three above commands. By doing so, you will instantly change your display brightness.
If your laptop is running on battery power, use the
-setdcvalueindex parameter instead.
Automatize via Task Scheduler
But there is a better way to do things. You can automatize the setting of display brightness.
To do so, go to
Here you can create new tasks and activate them based on your computer’s time.
Follow the steps in the animation below to create your own tasks. The animation shows how I created my Morning Brightness task:
I used the following commands in the
Add arguments (optional): -setactive 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c
As a safety measure, I also set a startup trigger for the Morning Brightness task. Just in case I slept in a bit and woke up after 8:00 AM.
In the Afternoon and Night-Time Brightness tasks, I used the corresponding power scheme GUIDs:
powercfg -setactive 381b4222-f694-41f0-9685-ff5bb260df2e
powercfg -setactive a1841308-3541-4fab-bc81-f71556f20b4a
More Power Schemes
In case you would like to be able to have more nuanced display brightness settings, you can create additional power schemes and trigger them via the Task scheduler, too.
To create an extra power scheme, use the following command scheme:
powercfg -duplicatescheme ExistingPowerSchemeGUIDtoDuplicate
This way you can create any number of power schemes and set your brightness hour by hour if you so wish.
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