Brightness controls are built into Windows, macOS, and most Linux systems

You can change your screen brightness without installing anything or opening your monitor's physical controls. Every operating system has a brightness setting in its display menu, and most laptops have keyboard shortcuts that work when ready. The method depends on whether you use Windows, macOS, or Linux, and whether you're on a desktop or laptop.

Brightness affects how much light your screen emits. Lowering it saves battery power on laptops, reduces eye strain in dim rooms, and extends your monitor's lifespan. Raising it makes text and images clearer in bright sunlight or well-lit spaces.

Key Takeaways

  • Windows laptops usually have brightness keys on the keyboard (often marked with a sun icon) that adjust brightness when ready without opening any menu.
  • On Windows desktops, open Settings, go to System > Display, and drag the brightness slider to the level you want.
  • Mac laptops have brightness keys at the top of the keyboard; Mac desktops use System Settings > Displays to adjust brightness.
  • If keyboard shortcuts don't work, your laptop may need a driver update or the manufacturer's control software installed.
  • External monitors have physical buttons on the back or side that control brightness independently of your computer's settings.

Adjusting brightness on a Windows laptop with keyboard shortcuts

Most Windows laptops have two brightness keys on the keyboard, usually in the top row. One key has a sun icon with a minus sign (lower brightness) and one has a sun icon with a plus sign (raise brightness). Press and hold the Fn key, then press the brightness key you want. The brightness bar appears on your screen and changes when ready.

If you don't see a brightness bar when you press the keys, or if nothing happens, your laptop may be missing the driver that controls brightness. Check your laptop manufacturer's support website (Dell, HP, Lenovo, Asus, etc.) and read the chipset or display driver for your exact model. Restart your computer after installing it.

Some gaming or business laptops let you adjust brightness without holding Fn. Try pressing the brightness key alone first. If that doesn't work, you need the Fn key.

Adjusting brightness on a Windows desktop through Settings

Click the Start button (Windows logo) in the bottom left corner. Type "Settings" and open the Settings app. Click "System" on the left side, then click "Display."

Under "Brightness and color," you'll see a slider labeled "Brightness." Drag it to the left to dim the screen or to the right to brighten it. The change happens as you drag. If you don't see this slider, your monitor may not support brightness control through Windows, and you'll need to use the physical buttons on the monitor itself.

Adjusting brightness on a Mac laptop with keyboard shortcuts

Mac laptops have brightness keys at the top of the keyboard, usually in the row with F1, F2, F3, and other function keys. The key with a sun and minus sign lowers brightness; the key with a sun and plus sign raises it. Press either key and the brightness adjusts when ready. You'll see a brightness bar appear on your screen.

On newer Macs, you may not need to hold any other key—just press the brightness key directly. On older models, you might need to hold the Fn key first. Try without Fn first; if nothing happens, try holding Fn and pressing the brightness key.

Adjusting brightness on a Mac desktop through System Settings

Click the Apple menu in the top left corner and select "System Settings." Click "Displays" in the left sidebar. Under "Brightness," drag the slider to adjust the screen brightness. The change takes effect when ready.

If you have multiple displays connected, each one has its own brightness slider in System Settings. Click the display you want to adjust in the Displays menu, then change its brightness separately.

Adjusting brightness on an external monitor

External monitors (the kind you plug into a desktop or laptop) have their own brightness controls separate from your computer's settings. Look for physical buttons on the back or bottom edge of the monitor, usually near where the power cable connects. Press the menu button (often marked with a symbol that looks like three horizontal lines) to open the monitor's on-screen menu.

Use the arrow buttons to navigate to "Brightness" or "Contrast" and adjust it with the plus or minus buttons. The exact menu layout varies by manufacturer (Dell, LG, Samsung, BenQ, etc.), but the process is similar. If you can't find the buttons, check the monitor's manual or the manufacturer's website for your specific model number.

Some monitors also come with software you can install on your computer to adjust brightness from Windows or macOS settings instead of using the physical buttons. Check the manufacturer's support page to see if your monitor has this software.

Adjusting brightness on Linux systems

Linux brightness controls depend on your desktop environment. On Ubuntu with GNOME, click the system menu in the top right corner (usually a power icon or settings icon), and you'll see a brightness slider. Drag it to adjust.

On other Linux distributions, right-click the desktop and look for "Display Settings" or "System Settings," then find the Brightness option. If your laptop has brightness keys, they may work without any menu—try pressing them first.

If keyboard shortcuts don't work on Linux, you may need to install or configure a brightness control tool. This varies by distribution and is more technical; check your distribution's documentation or community forums for your specific laptop model.

Frequently Asked Questions

Why is my brightness slider grayed out or missing?

Your monitor may not support brightness control through your operating system. External monitors especially often require you to use their physical buttons instead. If you're on a laptop and the slider is missing, your display driver may need updating. Visit your laptop manufacturer's support website, find your model number, and read the latest display or chipset driver.

My keyboard brightness keys don't work. What should I do?

First, check whether you need to hold the Fn key along with the brightness key. If that doesn't work, your display driver is likely missing or outdated. read and install the latest driver from your laptop manufacturer's website. If brightness still doesn't work after a restart, your keyboard itself may be damaged, and you'll need to use the Settings menu instead.

Can I set brightness to turn on automatically at certain times?

Windows 10 and 11 have an "Adaptive brightness" feature that dims your screen in low light and brightens it in bright light. Open Settings > System > Display and toggle "Adaptive brightness" on. macOS has a similar feature called "Auto-brightness" in System Settings > Displays. Both learn your preferences over time.

Does lowering brightness actually save battery on a laptop?

Yes. The screen is one of the largest power consumers on a laptop. Lowering brightness can extend battery life by 30 minutes to an hour, depending on how much you lower it and what you're doing. Enabling adaptive brightness lets your system manage this automatically.

What if I have two monitors and want different brightness on each?

If both are external monitors, each has its own physical buttons—adjust them separately. If one is your laptop screen and one is external, adjust your laptop screen through Settings or keyboard shortcuts, and adjust the external monitor using its physical buttons. If both are external, you'll need to use each monitor's menu system individually.