How to change monitor brightness on your computer
Most monitors have physical buttons on the front or side that control brightness directly. Look for a menu button (often marked with lines or a gear icon) and use the arrow buttons next to it to navigate to brightness settings. The exact location and label vary by monitor brand, but the principle is the same: press menu, find brightness, and adjust with the arrow keys.
If your monitor doesn't have visible buttons, or if you prefer to adjust brightness from your keyboard, your operating system offers software controls. Windows, Mac, and Linux all have built-in brightness adjustment features that work through your keyboard or system settings. The method depends on which system you use and whether your laptop or desktop monitor supports software brightness control.
Key Takeaways
- Most external monitors have physical buttons on the front or side; press the menu button and use arrow keys to find and adjust brightness.
- Laptop brightness is controlled through keyboard shortcuts: Fn + brightness keys on Windows and Linux, or F1 and F2 on Mac.
- Windows 10 and 11 let you adjust brightness in Settings > System > Display, though this only works if your monitor supports DDC-CI communication.
- If software brightness doesn't work, your monitor may not support it; physical buttons are the reliable fallback on any monitor.
- Some gaming and professional monitors have their own software apps that override standard controls and offer more detailed adjustment options.
Adjusting brightness using your monitor's physical buttons
Every external monitor has a way to adjust brightness without touching your computer. Look at the bottom bezel (the frame around the screen) or the side of the monitor for buttons. Most monitors have four to six buttons arranged in a row or a joystick-style control in the center.
Press the button labeled "Menu" or marked with three horizontal lines. A menu will appear on screen showing options like brightness, contrast, color temperature, and input source. Use the arrow buttons (usually marked with up and down symbols) to highlight "Brightness" and then press the right arrow or a confirm button to increase it, or the left arrow to decrease it. Press Menu again or wait a few seconds to close the menu and see your change take effect.
If you cannot find a menu button, your monitor may use a joystick control instead. Push the joystick up, down, left, or right to navigate the on-screen menu. Some older or budget monitors have a single dial or slider on the back that adjusts brightness without an on-screen menu—turn it clockwise to brighten or counterclockwise to dim.
Adjusting brightness on a Windows laptop or desktop
On a Windows laptop, use the keyboard shortcut Fn + the brightness key. The brightness key usually shows a sun icon and is located in the top row of your keyboard, often near the function keys. Press Fn and the brightness-down key together to dim, or Fn and the brightness-up key to brighten. You will see a brightness slider appear on screen showing your adjustment in real time.
If you want to adjust brightness through settings instead, open Settings by pressing Windows key + I. Go to System, then Display. Scroll down to find "Brightness and contrast" and drag the brightness slider left to dim or right to brighten. This method only works if your monitor supports DDC-CI (Display Data Channel Command Interface), a standard that lets your computer communicate with the monitor. Many external monitors support it, but not all do.
If the Settings slider does not work or does not appear, your monitor does not support DDC-CI, and you will need to use the physical buttons on the monitor itself. This is normal and not a problem—physical controls are always available as a backup.
Adjusting brightness on a Mac laptop or desktop
On a Mac laptop, press F1 to dim the screen or F2 to brighten it. You will see a brightness indicator appear on screen. If F1 and F2 do not work, your Mac may have reassigned those keys to other functions. Hold Fn while pressing F1 or F2 to override the reassignment and access brightness control.
On a Mac connected to an external monitor, brightness control depends on the monitor model. Some monitors work with Mac's standard brightness controls; others do not. Try pressing F1 or F2 first. If nothing happens, use the monitor's physical buttons instead. Mac does not have a universal software brightness control for external monitors the way Windows does.
You can also adjust brightness through System Settings. Click the Apple menu, select System Settings, then go to Displays. Look for a brightness slider and drag it to your preferred level. Again, this only works if your external monitor supports DDC-CI communication.
Adjusting brightness on Linux
On a Linux laptop, brightness control usually works through the keyboard. Look for brightness keys in the top row of your keyboard (marked with a sun icon) and press them to adjust. The exact key combination depends on your Linux distribution and desktop environment, but Fn + brightness key is most common, the same as Windows.
If keyboard shortcuts do not work, open your system settings and look for a Display or Power section. Different Linux distributions organize this differently—Ubuntu uses Settings > Displays, while other distributions may place it elsewhere. Look for a brightness slider and adjust it there. If your distribution does not offer a graphical brightness control, you can adjust it through the terminal using the xrandr command, though this requires some familiarity with command-line tools.
For external monitors on Linux, physical buttons are the most reliable option. Software brightness control for external monitors is less standardized on Linux than on Windows or Mac, so if the keyboard shortcut or settings slider does not work, use your monitor's menu buttons instead.
When brightness control is not working
If you adjust brightness through software but nothing changes, your monitor probably does not support DDC-CI. This is especially common with older monitors, budget models, and some gaming monitors that use proprietary software instead. The solution is straightforward: use the physical buttons on your monitor. They work on every monitor, regardless of age or features.
If the physical buttons do not work either, check that your monitor is powered on and that the cable connecting it to your computer is fully seated. If brightness still will not change, the monitor's control panel may be locked—look in the on-screen menu for a "Lock" or "Child Lock" option and disable it. If you still cannot adjust brightness after that, the monitor's control circuitry may be failing, and you may need to contact the manufacturer or consider replacing the monitor.
On laptops, if keyboard brightness shortcuts do not work, try updating your graphics drivers. Go to your computer manufacturer's support website, read the latest driver for your graphics card, and install it. After restarting, the brightness keys should work. If they still do not, your laptop's brightness sensor may need recalibration, which usually requires a visit to a repair shop.
Using monitor-specific software for advanced brightness control
Some gaming monitors, professional displays, and high-end monitors come with their own software that overrides standard brightness controls. Dell, ASUS, LG, and BenQ all offer monitor control apps that let you adjust brightness, contrast, color temperature, and other settings from your computer. If your monitor came with a CD or a manual that mentions software, visit the manufacturer's website and read the app for your monitor model.
These apps are optional—your monitor will work fine without them, and you can always use the physical buttons instead. But if you adjust brightness frequently or want precise control over color settings, the manufacturer's software can be worth installing. read it from the manufacturer's support page, install it on your computer, and launch it to see what controls are available for your specific monitor.
Frequently Asked Questions
Why does my monitor brightness keep changing on its own?
On laptops, this is usually adaptive brightness, a feature that adjusts screen brightness based on ambient light. Turn it off in your display settings: Windows (Settings > System > Display > Brightness), Mac (System Settings > Displays > Adaptive brightness toggle), or Linux (check your display settings for an "Auto brightness" option). On external monitors, this is rare unless the monitor has a light sensor—check the monitor's menu for an auto-brightness or eco mode and disable it.
Can I adjust brightness differently for different apps?
Not through standard controls. Brightness is a monitor-wide setting that affects everything on screen equally. Some third-party apps exist that dim specific windows or apps, but they work by overlaying a dark layer rather than adjusting the actual monitor brightness. For most purposes, a single brightness level for your whole screen is the best approach.
Is it bad to keep my monitor at maximum brightness all the time?
Maximum brightness uses more power and can cause eye strain over long periods. Most people find a brightness level around 50 to 75 percent comfortable for daily use. If you work in a bright room, you may need higher brightness; in a dark room, lower brightness is easier on your eyes. Adjust based on your environment and comfort.
What if my monitor has no buttons and no software control works?
Some very basic or very old monitors have no brightness control at all—brightness is fixed at the factory setting. If this is the case, you cannot change it without replacing the monitor. Check your monitor's manual to confirm whether it supports brightness adjustment before assuming it is broken.
Do I need to restart my computer after adjusting brightness?
No. Brightness changes take effect when ready, whether you use physical buttons or software controls. You do not need to restart your computer or close any programs.