Change your Mac display’s brightness
You can adjust the display’s brightness manually or automatically.
Use the brightness function keys
If the screen seems too light or too dark, you can adjust your display’s brightness.
On your Mac, press the increase brightness key or the decrease brightness key (or use the Control Strip).
Automatically adjust brightness
If your Mac has an ambient light sensor, choose Apple menu > System Settings, then click Displays in the sidebar. (You may need to scroll down.)
Turn on “Automatically adjust brightness” on the right.
If you don’t see the “Automatically adjust brightness” option, you can manually adjust the brightness.
Manually adjust brightness
On your Mac, choose Apple menu > System Settings, then click Displays in the sidebar. (You may need to scroll down.)
Drag the Brightness slider on the right to adjust the brightness of your display.
Depending on the type of display connected to your Mac, you may also see a Contrast slider that you can use to adjust the display’s contrast.
For specific information about the brightness of your display, check the documentation that came with your display.