How to change your screen brightness on Windows 11 and Mac
A screen that is too dim strains your eyes, and one that is too bright is just as bad at night. Here is how to fix it in a few seconds on Windows 11 and on a Mac.
Brightness is one of those settings you change many times a day. You move from a sunny window to a dark room, or from a bright office to a late-night movie. Every laptop has a quick way to do it, and a few slower ways that help when the quick one fails.
We will start with Windows 11, then the Mac, then what to do if nothing seems to work.
Change screen brightness on Windows 11
Fastest: the brightness keys
Most laptops have two keys with a small sun on them, often on the top row with the function keys. Press the one with the smaller or dimmer sun to lower brightness. Press the other to raise it. On some laptops you need to hold the Fn key at the same time.
Quick Settings
- Press Windows + A. You can also click the Wi-Fi, speaker or battery icons near the clock.
- Find the Brightness slider, the one with a sun icon.
- Drag it left to dim the screen, or right to brighten it.
In Settings
- Open Settings. A quick way is to press Windows + I.
- Go to Settings › System › Display.
- Drag the Brightness slider.
The Display page is also where you can find the options that let Windows adjust brightness on its own when the lighting changes or when you are on battery. If your screen keeps changing by itself, look there first.
No brightness slider? That usually means you are using an external monitor. Windows only shows the slider for the built-in screen of a laptop. Use the buttons on the monitor itself instead, usually along the bottom edge or on the back.
Change screen brightness on a Mac
Fastest: the brightness keys
On a MacBook or a Magic Keyboard, press the brightness keys on the top row. They show a small sun. One makes the screen dimmer and the other makes it brighter. Some MacBooks have a Touch Bar instead, and you can use the Control Strip there.
In System Settings
- Click the Apple menu in the top-left corner and choose System Settings.
- Click Displays in the sidebar.
- Drag the Brightness slider.
If your Mac has an ambient light sensor, you will also see Automatically adjust brightness on the same page. Turn it on and the Mac changes the screen to match the room around you. Apple says this can also help the battery last longer.
Some external displays show a Contrast slider here too. It is a different setting from brightness, so try brightness first.
Screen slow to get bright? Press the brightness-up key once to make sure brightness was not turned all the way down. Then try turning on automatic brightness.
If brightness will not change
- Try the other method. If the keys do nothing, use the slider. If the slider is missing, check whether an external monitor is connected.
- Check for a setting that fights you. On Windows, automatic brightness can move the slider back. On a Mac, the Automatically adjust brightness switch does the same thing. Turn it off if you want full control.
- Restart. A restart fixes many small display glitches.
- Keys that need Fn. On some laptops the sun keys only work together with Fn.
Ask Key to change it for you
If you would rather not hunt for a key or a slider, you can just say what you want. Key is a free assistant that lives on your computer. It works on Windows 10 and 11, and on any Mac with macOS 11 Big Sur or newer. You can speak to it or type to it, and both give the same result.
A short request is enough, such as "Turn the brightness down". Key opens the real settings, makes the change, and tells you what it did. While it works, a small panel shows what it is doing, and you can stop it at any point. It also reads the result back before it reports it, and if it could not check, it says so.
KeyVoiceTurn the brightness down
I turned your screen brightness down.
Brightness is only one of the settings Key can change. For more, see how to change brightness, dark mode and other settings by voice. For a wider look, read what an AI assistant on your PC can do every day.
A quick summary
- Windows 11: press Windows + A and drag the Brightness slider, or go to Settings › System › Display.
- Mac: use the brightness keys, or go to System Settings › Displays and drag the Brightness slider.
- No slider on Windows: you are probably on an external monitor. Use its own buttons.
- With Key: say or type "Turn the brightness down".
Try Key free
Speak to it or type to it. It opens your apps, finds your files and changes your settings, then tells you what it did.
Free, no card. Windows 10 or 11, macOS 11 or newer.