The fastest way to adjust brightness depends on your monitor type

Most monitors have physical buttons on the front or side that control brightness directly. Look for a button labeled with a sun symbol, a plus and minus pair, or a menu icon. Press and hold the menu button until an on-screen display appears, then use the plus or minus buttons to raise or lower brightness. This works the same way whether you use Windows, Mac, or Linux — the monitor itself handles the adjustment, not your operating system.

If your monitor has no visible buttons, check the back or underside for a control panel. Some flat-panel monitors hide the buttons along the bottom edge or on a side panel. Your monitor's manual will show you exactly where they are; you can usually find the manual online by searching the model number (printed on a sticker on the back).

If you cannot find physical buttons and your monitor is built into a laptop or all-in-one computer, you will need to adjust brightness through your operating system instead, which is covered below.

Key Takeaways

  • Desktop monitors almost always have physical buttons on the front or side that control brightness without touching your computer.
  • Press and hold the menu button until an on-screen display appears, then use plus and minus buttons to adjust.
  • Laptop and all-in-one computers require brightness adjustment through Windows, Mac, or Linux settings instead.
  • If your monitor has no buttons, the model number on the back will help you find the manual online.
  • Some USB-connected monitors and gaming displays use software instead of physical buttons, which the manual will explain.

Adjusting brightness on a Windows computer

If your monitor has no physical buttons or you are using a laptop, open the Windows Settings app by pressing the Windows key and typing "Settings." Go to System, then Display. You will see a brightness slider under "Brightness and color." Drag it left to darken the screen or right to brighten it. This change affects your entire display when ready.

On Windows 10 and 11, you can also use the Quick Settings menu. Press Windows key + A to open it, and you will see a brightness slider at the top. This is the fastest method if you need to adjust brightness often throughout the day.

Some laptops also have keyboard shortcuts: Fn + F5 or Fn + F6 usually control brightness, with the function key held down while you press the brightness key. The brightness keys are marked with a sun symbol and are usually in the top row of your keyboard.

Adjusting brightness on a Mac

On a Mac laptop, press the brightness down key (marked with a sun and minus sign) or brightness up key (marked with a sun and plus sign) in the top row of your keyboard. Hold the key down to adjust continuously, or tap it once for small changes. This is the primary method for Mac laptops.

If you are using an external monitor connected to a Mac, use the monitor's physical buttons instead. Mac system settings do not control external monitor brightness the way Windows does. If the monitor has no buttons, check whether it came with software — some higher-end monitors include a small app you can read from the manufacturer's website.

On newer Mac models with an M1 or M2 chip, you can also go to System Settings, then Displays, and adjust brightness there, though the keyboard shortcut is faster for most users.

Adjusting brightness on Linux

The method depends on your Linux distribution and desktop environment. On Ubuntu with GNOME, click the system menu in the top right corner, then click the brightness slider. On other distributions, look for a Settings or System Settings process, then navigate to Display or Screen.

If you cannot find a brightness control in your settings, your monitor likely requires physical button adjustment. Some Linux systems also respond to keyboard shortcuts like Fn + brightness keys on laptops, though this varies by hardware.

For advanced users, you can also adjust brightness from the command line using tools like xrandr or brightnessctl, but the graphical method is simpler for most people.

When to use monitor buttons instead of computer settings

If your desktop monitor has physical buttons, use them instead of your computer's settings. Monitor buttons give you direct control over the hardware and do not depend on your operating system. This means the brightness stays at your chosen level even if you restart your computer or switch between user accounts.

Computer settings (Windows, Mac, or Linux) are better for laptops and all-in-one computers where the display is built in. They also let you set different brightness levels for different times of day if you use features like Windows Night Light or Mac Night Shift, which reduce blue light in the evening.

If you have both a laptop and an external monitor, adjust the laptop screen through your operating system and the external monitor through its physical buttons. This gives you the most control over each display separately.

Troubleshooting when brightness will not change

If the brightness slider in Windows or Mac does not work, your graphics driver may need an update. On Windows, right-click the Start button, select Device Manager, expand Display adapters, right-click your graphics card, and select Update driver. On Mac, go to System Settings, then General, then Software Update.

If monitor buttons do not work, make sure you are pressing the correct button. Some monitors require you to hold the button for two seconds before the menu appears. If the on-screen display never shows up, the monitor may be in a locked mode — check the manual for an unlock procedure, usually a combination of button presses.

For laptop keyboards, make sure the Fn key is working. Try Fn + Esc, which toggles Fn lock on some models. If brightness keys still do not respond, update your keyboard or trackpad drivers through Device Manager (Windows) or Software Update (Mac).

Frequently Asked Questions

Why does my monitor brightness keep changing on its own?

Windows and Mac both have automatic brightness features that adjust the screen based on ambient light. On Windows, go to Settings > System > Display and turn off "Automatically adjust brightness." On Mac, go to System Settings > Displays and uncheck "Automatically adjust brightness." Some monitors also have a sensor that does this independently — check your monitor's manual for a sensor or auto-brightness setting.

Can I set different brightness levels for different programs?

Your operating system does not offer per-program brightness control. However, you can use features like Windows Night Light or Mac Night Shift to reduce brightness and blue light during certain hours. Some professional software for photo or video editing includes its own display calibration tools, but these are separate from your monitor's brightness setting.

Is it bad for my monitor to run at full brightness all the time?

Running at full brightness does not damage modern monitors, but it uses more power and may reduce the lifespan of the backlight slightly over many years. Most people find that 50 to 75 percent brightness is comfortable for daily work and reduces eye strain. Adjust based on your room's lighting and what feels comfortable to you.

What if my monitor has a brightness button but it does not work?

First, check that the monitor is powered on and receiving a signal from your computer. If the on-screen menu does not appear when you press the button, try holding it down for three seconds. If nothing happens, the button may be stuck or the monitor may be in a locked mode — consult your monitor's manual for a reset procedure, or contact the manufacturer.