The fastest way to adjust brightness on your screen

On most computers, you can change screen brightness in seconds using your keyboard. Look for keys with a sun symbol or brightness bars — usually on the F1 through F12 row at the top. Hold the Fn key (bottom left of your keyboard) and press the brightness key to dim or brighten the screen. If your keyboard has dedicated brightness buttons without the sun symbol, you may not need to hold Fn.

If your keyboard has no brightness keys, or if they do not work, you can adjust brightness through your operating system settings instead. This takes a few more clicks but works on any computer.

Key Takeaways

  • Most keyboards have brightness keys in the F1–F12 row marked with a sun symbol; hold Fn and press them to adjust when ready.
  • Windows users can open Settings, go to System, then Display, and drag the brightness slider left or right.
  • Mac users can open System Settings, select Displays, and move the brightness slider, or use Control Center from the menu bar.
  • If brightness keys do nothing, your graphics driver may need updating, which you can do through Device Manager on Windows or Software Update on Mac.
  • External monitors have their own brightness controls on the back or side of the screen, separate from your computer's settings.

Adjusting brightness on Windows

Open the Settings app by pressing the Windows key and typing "Settings," then press Enter. Click System on the left side, then Display. You will see a brightness slider under "Brightness and color" — drag it to the left to dim or to the right to brighten.

If you do not see a slider, your graphics driver may not be installed or may be out of date. Open Device Manager by right-clicking the Start button and selecting Device Manager. Find Display adapters, right-click your graphics card, and select Update driver. Windows will search for the latest version and install it automatically.

You can also adjust brightness from the Quick Settings panel. Press Windows key + A to open it, and you will see a brightness slider at the top.

Adjusting brightness on Mac

Open System Settings by clicking the Apple menu in the top left and selecting System Settings. Click Displays on the left side. You will see a brightness slider — drag it left to dim or right to brighten. The change takes effect when ready.

You can also adjust brightness from Control Center. Click the Control Center icon in the top right corner of your menu bar, then drag the brightness slider. This is faster if you adjust brightness often.

Some Mac keyboards have brightness keys marked with a sun symbol in the F1 and F2 positions. Press them directly without holding any other key to adjust brightness.

Using brightness controls on an external monitor

If you have plugged an external monitor into your computer, that monitor has its own brightness setting separate from your computer's screen. Look for physical buttons on the back or bottom edge of the monitor, usually marked with a sun symbol or labeled Menu.

Press the Menu button to open the monitor's on-screen display. Use the arrow buttons to navigate to Brightness, then press the plus or minus button to adjust. The exact steps vary by monitor brand, so check the manual if you cannot find the brightness option.

Adjusting the monitor's brightness does not change your computer's brightness setting — they work independently. If your monitor is very dim, check both the monitor's physical controls and your computer's settings to find which one needs adjustment.

When brightness keys do not work

If you press the brightness keys and nothing happens, the most common cause is a missing or outdated graphics driver. On Windows, open Device Manager (right-click Start, select Device Manager), expand Display adapters, right-click your graphics card, and select Update driver. Let Windows search online and install the latest version.

On Mac, brightness keys usually work without any driver update, but if they do not, restart your computer. If the problem continues, open System Settings, click Keyboard, then select Keyboard Shortcuts. Look for Display in the left menu and make sure the brightness shortcuts are not disabled.

Some laptops have a physical switch or key combination that disables brightness controls. Check your keyboard for a key with a brightness symbol and a lock icon, or look in your laptop's manual. If you find one, toggle it to enable brightness control again.

Brightness settings that save power

Lowering your screen brightness reduces the power your computer uses, which extends battery life on laptops. On Windows, you can set brightness to adjust automatically based on the time of day. Open Settings, go to System, then Display, and toggle on "Brightness" under "Adaptive brightness." Your screen will dim in low light and brighten in bright conditions.

You can also set different brightness levels for when your laptop is plugged in versus running on battery. In Settings, go to System, then Power, then scroll down and click Additional power settings. Click Change plan settings next to your current plan, then Change advanced power settings. Expand Display, then Brightness, and set separate values for Plugged in and On battery.

On Mac, open System Settings, click Displays, and toggle on "Automatically adjust brightness." Your screen will brighten or dim based on the ambient light in your room, which also saves battery power.

Troubleshooting brightness that is stuck or unresponsive

If your brightness is stuck at maximum or minimum and will not change, restart your computer first. This clears temporary settings that may be causing the problem.

If brightness still will not adjust after restart, check whether your graphics driver is up to date. On Windows, open Device Manager, right-click your graphics card under Display adapters, and select Update driver. On Mac, click the Apple menu, select System Settings, then Software Update, and install any available updates.

If you have an external monitor that is stuck at one brightness level, check the monitor's physical buttons on the back or side. Some monitors have a lock feature that prevents brightness changes — look for a button labeled Lock or Menu Lock and press it to unlock the controls.

Frequently Asked Questions

Why is my screen brightness stuck at full brightness?

Your graphics driver may be outdated or missing. Open Device Manager on Windows (right-click Start, select Device Manager), find your graphics card under Display adapters, right-click it, and select Update driver. On Mac, go to System Settings, click Software Update, and install any available updates.

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

Windows does not have a built-in schedule, but you can use adaptive brightness, which adjusts based on ambient light. On Mac, the same feature exists. Alternatively, you can manually adjust brightness when you need to, or use third-party apps designed for scheduled brightness changes.

Does lowering brightness actually save battery power?

Yes. Your screen uses a significant amount of battery power, especially on laptops. Lowering brightness can extend battery life by 30 minutes to several hours depending on how much you lower it and what you are doing.

My external monitor is very dim even though my computer brightness is high. What should I do?

Your monitor has its own brightness control separate from your computer. Look for physical buttons on the back or bottom of the monitor, press Menu, navigate to Brightness, and increase it. If you cannot find the buttons, check your monitor's manual for the location and labeling.

Do I need to restart my computer after updating my graphics driver?

Usually yes. After updating your graphics driver, Windows or Mac will prompt you to restart. Do so to explore the update fully. If brightness keys still do not work after restart, the driver may not have installed correctly — try updating again.