The quickest way to dim your screen

On most computers, you can lower brightness using keyboard shortcuts or your system settings. The fastest method depends on whether you use Windows or Mac, and whether your keyboard has dedicated brightness keys.

If your keyboard has brightness keys — usually marked with a sun icon and located on the function row at the top — hold Fn and press the key with the down arrow or dimmer symbol. This works when ready on most laptops. On desktop computers without these keys, you'll need to go through your system settings instead.

If the keyboard shortcut doesn't work, your computer may not recognize the brightness hardware, or the driver needs updating. In that case, the settings method below will always work.

Key Takeaways

  • Windows laptops usually respond to Fn + brightness key (the down arrow or dimmer symbol on your keyboard), which is the fastest way to dim the screen.
  • Mac laptops use the brightness keys without holding Fn — just press the key with the down arrow symbol on the top row.
  • If keyboard shortcuts don't work, open Settings on Windows or System Settings on Mac and search for "brightness" to adjust it manually.
  • Desktop monitors have physical buttons on the monitor itself, usually on the bottom or side, labeled with brightness or a sun icon.
  • If brightness controls are missing or greyed out, your graphics driver may need updating, which you can do through Device Manager on Windows.

Windows laptop brightness adjustment

On a Windows laptop, the keyboard shortcut is usually your first option. Look at the function row (the top row of keys with F1, F2, etc.). Find the key with a sun symbol and a down arrow — this is your brightness-down key. Hold Fn (bottom left of your keyboard) and press that key. The brightness should drop when ready, and you may see a brightness slider appear on your screen.

If that doesn't work, open Settings by pressing Windows key + I. Type "brightness" in the search box. Under "Brightness and color," you'll see a slider labeled "Brightness." Drag it to the left to dim the screen. This setting affects your entire display and works on any Windows 10 or Windows 11 machine.

Some older Windows laptops also have a brightness control in the taskbar. Right-click the battery icon in the bottom right corner and look for a brightness slider. If you see one, drag it left to lower brightness.

Mac laptop brightness adjustment

On a Mac, the brightness keys are on the top row of your keyboard — look for the sun symbol with a down arrow. Unlike Windows, you do not hold Fn; just press the brightness-down key directly. The screen will dim, and you'll see a brightness indicator appear on the display.

If the keyboard shortcut doesn't respond, open System Settings (the gear icon in your dock or Applications folder). Click Displays in the sidebar. You'll see a "Brightness" slider — drag it left to dim. On newer Macs with an M1 or M2 chip, this setting is usually very responsive.

If you have an external monitor connected to your Mac, the Mac's brightness controls only affect the built-in screen. For the external monitor, use the physical buttons on the monitor itself.

Desktop monitor brightness control

Desktop monitors don't have keyboard shortcuts for brightness. Instead, look for physical buttons on the monitor itself — usually on the bottom edge or the right side. These buttons are often labeled with a sun icon or marked "Menu," "Brightness," or "+/−" symbols.

Press the button labeled for brightness or Menu, then use the arrow buttons to navigate to a brightness option. Once you find it, use the up and down arrows to adjust. Some monitors show an on-screen display (a small menu that appears on the screen) when you adjust brightness; others don't give any visual feedback, so adjust slowly and check the result.

If your monitor has no visible buttons, check the back or underside — some models hide controls there. Refer to your monitor's manual if you're unsure where the controls are located. You can usually find the manual by searching your monitor's model number online.

When brightness controls are missing or greyed out

If you open Settings and the brightness slider is missing, greyed out, or won't move, your graphics driver likely needs attention. On Windows, this is usually fixable through Device Manager.

Press Windows key + X and select Device Manager. Look for Display adapters and click the arrow to expand it. Right-click the graphics card listed (often Intel, NVIDIA, or AMD) and select Update driver. Choose "Search automatically for updated driver software." Windows will search for and install the latest version if one is available.

After the update completes, restart your computer. The brightness controls should now work. If they still don't, right-click the graphics card again and select Properties, then click the Driver tab to confirm the driver date is recent. If it's very old, you may need to visit the manufacturer's website (Intel, NVIDIA, or AMD) and read the driver directly.

Brightness and eye strain

Lowering brightness is often the right choice if you're working in a dim room or if your screen feels too bright for comfort. A screen that's too bright can cause eye fatigue, especially in low-light environments. A good rule is to match your screen brightness roughly to the brightness of the room around it.

If you find yourself constantly adjusting brightness throughout the day, consider enabling adaptive brightness (on Windows) or auto-brightness (on Mac). These features use your computer's light sensor to adjust brightness automatically based on your surroundings. On Windows, search Settings for "adaptive brightness" and toggle it on. On Mac, go to System Settings > Displays and check "Auto-brightness."

Frequently Asked Questions

Why won't my brightness keys work?

Brightness keys often don't work if your graphics driver is outdated or if your keyboard isn't recognized by your system. Try updating your graphics driver through Device Manager (Windows) or System Settings (Mac). If you're using an external keyboard, it may not have brightness controls — use your system settings instead.

Can I set different brightness levels for different times of day?

Yes. On Windows 11, search Settings for "night light" to reduce blue light in the evening, which also dims the screen slightly. On Mac, go to System Settings > Displays > Night Shift. Both features let you schedule automatic adjustments. For more control, third-party apps like f.lux (available for both Windows and Mac) let you set custom brightness schedules.

Is it bad to keep my screen very dim?

Very dim screens can strain your eyes because you're forcing them to work harder to see the content. The best brightness is one that matches your environment — bright enough to see clearly without being so bright that it causes glare or discomfort. If you're in a dark room, a moderately dim screen is fine; in a bright room, you'll need higher brightness.

My external monitor brightness won't change from the keyboard. What do I do?

External monitors don't respond to your computer's brightness controls. You must use the physical buttons on the monitor itself. Look for buttons on the bottom, side, or back of the monitor, usually marked with a sun icon or brightness symbol. If your monitor has no buttons, check the manual — some models use an on-screen menu accessed through a single button.

Does lowering brightness save battery on a laptop?

Yes, significantly. The screen is one of the largest power consumers on a laptop. Lowering brightness can extend battery life by 30 minutes to an hour or more, depending on how much you reduce it. If battery life matters, dimming the screen is one of the most effective steps you can take.