The fastest way to dim your screen

On most computers, you can lower brightness in seconds using your keyboard. Look for keys with a sun symbol — usually on the F-keys at the top of your keyboard. Press the key with the dimmer sun (often F11 or F5, depending on your brand) to turn brightness down. Each press makes the screen darker.

If your keyboard doesn't have brightness keys, or if they don't work, you can adjust brightness through your operating system settings instead. This takes a bit longer but works on every computer.

Key Takeaways

  • Brightness keys on your keyboard (usually marked with a sun symbol) are the quickest way to dim your screen — press the dimmer sun icon repeatedly until the brightness feels right.
  • Windows computers let you adjust brightness through Settings > System > Display, or by right-clicking the desktop and selecting Display Settings.
  • Mac computers have brightness controls in System Preferences > Displays, or you can use the Touch Bar if your Mac has one.
  • If keyboard brightness keys don't work, check your manufacturer's control software — Dell, HP, Lenovo, and others often include their own brightness tools.
  • Lowering brightness saves battery power on laptops and reduces eye strain during evening use.

Brightness keys on Windows laptops

Most Windows laptops have brightness keys built into the keyboard. Look at the F-keys (F1 through F12) at the top — you'll see two keys with sun symbols. One sun looks brighter (more rays), and one looks dimmer (fewer rays). The dimmer sun is your brightness-down key.

Press and hold the dimmer sun key for a second or two. You'll see a brightness bar appear on your screen, usually in the center or corner. Keep pressing until the bar reaches the level you want. Release the key when you're done.

If nothing happens when you press the sun keys, you may need to hold the Fn key (usually in the bottom left corner) at the same time. Try Fn + dimmer sun together. Some laptops require this combination; others don't.

Brightness adjustment on Windows desktops and tablets

Desktop monitors don't have keyboard brightness controls, so you'll adjust brightness through Windows settings instead. Right-click anywhere on your desktop (the blank area, not on an icon) and select Display Settings from the menu that appears.

In the Display Settings window, scroll down until you see a section labeled Brightness and color. You'll see a slider under "Brightness." Click and drag the slider to the left to make your screen darker, or to the right to make it brighter. The change happens when ready as you move the slider.

If you don't see a brightness slider, your monitor may not support software brightness control. In that case, look for physical buttons on the monitor itself — usually on the bottom or side. These buttons let you adjust brightness directly on the hardware.

Brightness adjustment on Mac computers

Mac laptops have brightness keys on the keyboard, usually in the F-keys row. Look for keys with a sun symbol — the one with fewer rays lowers brightness. Press it repeatedly until your screen reaches the brightness you want.

If your Mac has a Touch Bar (a thin screen at the top of the keyboard instead of physical function keys), swipe left on the brightness icon to dim the screen. The brightness icon looks like a sun and appears when you press the Fn key or swipe from the right side of the Touch Bar.

To adjust brightness through settings, click the Apple menu in the top left corner and select System Preferences (or System Settings on newer Macs). Then click Displays and drag the Brightness slider to the left.

Brightness controls in manufacturer software

Dell, HP, Lenovo, ASUS, and other computer makers often include their own brightness control programs. These programs may offer more options than the keyboard keys or operating system settings — for example, you might be able to set different brightness levels for different times of day.

To find your manufacturer's software, open the Start menu (Windows) or Applications folder (Mac) and search for your brand name plus "control center" or "settings." Common names include Dell Power Manager, HP Command Center, and Lenovo Vantage. If you find the program, open it and look for a Display or Brightness section.

If you're not sure which manufacturer made your computer, check the sticker on the back or bottom of your device. You can also right-click the Start menu, select System, and look for the manufacturer name in the "Device name" field.

Why you might want to lower brightness

Dimming your screen saves battery power on laptops — the brighter your screen, the more energy it uses. If you're working on battery and need your laptop to last longer, lowering brightness is one of the fastest ways to extend your time away from a charger.

Lowering brightness also reduces eye strain, especially in dim rooms or during evening hours. Many people find that a dimmer screen feels more comfortable for long work sessions. Some computers include a Night Light or Night Shift feature that not only dims the screen but also shifts colors toward warmer tones, which can help you sleep better if you use your computer in the evening.

Troubleshooting brightness keys that don't work

If your brightness keys don't dim the screen, the most common cause is that they need the Fn key held down at the same time. Try pressing Fn + the dimmer sun key together. If that works, your keyboard is set to require Fn for brightness control.

If Fn + brightness key still doesn't work, restart your computer. Sometimes brightness drivers (the software that controls brightness) stop responding until you restart. After restarting, try the brightness keys again.

If brightness keys still don't respond after a restart, check your manufacturer's website for driver updates. Go to your brand's support page, enter your computer model number, and read any available display or chipset drivers. Install them and restart again. If you're not comfortable installing drivers, use the Windows or Mac settings method instead — it works on every computer.

Frequently Asked Questions

Can I set brightness to turn down automatically at a certain time?

Yes. Windows has a feature called Night Light that dims your screen and shifts colors toward warmer tones at a time you choose. Go to Settings > System > Display and turn on Night Light, then set the schedule. Mac has a similar feature called Night Shift in System Preferences > Displays.

Why does my brightness slider not go all the way down?

Some computers have a minimum brightness level to prevent the screen from becoming completely black. This is intentional — it keeps you from accidentally making the screen unreadable. If you need it darker, try using Night Light or Night Shift, which can dim the screen further while also adding a warmer color tone.

Does lowering brightness actually save battery power?

Yes, significantly. The screen is one of the biggest power consumers on a laptop. Lowering brightness to a comfortable level can add an hour or more of battery life, depending on how bright you had it before. The dimmer you go, the more battery you save.

My monitor has buttons but I can't find the brightness control?

Monitor buttons usually control brightness, contrast, and input source. Press each button and look for an on-screen menu. Once the menu appears, use the buttons to navigate to Brightness or a similar option. If you can't find it, check your monitor's manual — you can usually find it online by searching your monitor model number plus "manual."

Is there a way to lock my brightness so it doesn't change?

On Windows, you can turn off automatic brightness adjustment in Settings > System > Display > Brightness and color. Toggle off "Change brightness automatically." On Mac, go to System Preferences > Displays and uncheck "Automatically adjust brightness." After that, your brightness will stay at whatever level you set it to.