The quickest way to brighten your screen

Most computers let you adjust brightness through a keyboard shortcut or settings menu. On Windows, press the Windows key and the letter A together to open Quick Settings, then drag the brightness slider to the right. On Mac, press F2 (or Fn + F2 on newer models) to raise brightness, or click the Control Center icon in the top-right corner and adjust the brightness slider there. If your keyboard has brightness keys marked with a sun symbol, those work too — usually Fn plus the brightness key.

If the keyboard shortcut does not work, your graphics driver may need updating, or your monitor may have its own brightness control. Check the back or side of your monitor for physical buttons or a menu dial, and look for a brightness or contrast setting there.

Key Takeaways

  • Windows and Mac both have brightness controls in their quick settings menus, accessible in seconds without opening full settings.
  • Keyboard shortcuts using the sun symbol keys or function keys work on most laptops and some desktop keyboards.
  • External monitors have their own brightness controls on the physical device, separate from your computer's settings.
  • If brightness keys stop working, updating your graphics driver often fixes the problem.
  • Automatic brightness adjustment can reduce eye strain, and you can turn it on or off depending on your work environment.

Adjusting brightness in Windows settings

If Quick Settings does not appear or the slider is missing, open the full Settings app. Press Windows key + I, then go to System and select Display. You will see a brightness slider under Brightness and color. Drag it to the right to brighten the screen.

Below the brightness slider, you will find a toggle for Adaptive brightness (sometimes called auto-brightness). When this is on, Windows adjusts your screen brightness based on the light in your room, which can reduce eye strain. If you work in a room with changing light throughout the day, leaving this on is often more comfortable than a fixed brightness level. If you find it distracting or if it makes the screen flicker, turn it off.

Adjusting brightness on Mac

On Mac, the fastest route is the Control Center. Click the Control Center icon in the top-right corner of the menu bar, then look for the brightness slider. Drag it to the right. If you do not see a brightness slider in Control Center, go to System Settings, click Displays, and adjust the brightness slider there.

Mac also has an Automatic brightness option in Displays settings. When it is on, your Mac uses the built-in light sensor to match screen brightness to your surroundings. Like Windows adaptive brightness, this reduces eye strain in rooms where natural light changes throughout the day. You can turn it on or off depending on whether you prefer a consistent brightness level or one that adjusts automatically.

Checking your monitor's own brightness control

External monitors — the separate screens you plug into a desktop computer — have their own brightness settings that work independently of your computer. Look for physical buttons or a dial on the back, bottom, or side of the monitor. These are usually labeled with a sun symbol or the word Brightness. Press or turn them to adjust the monitor's brightness directly.

Some monitors also have an on-screen menu you can access by pressing a button labeled Menu or Settings. Once the menu appears on your screen, use the arrow buttons to navigate to Brightness or Contrast and adjust from there. If your monitor is very old or has no visible controls, check the manual or the manufacturer's website for instructions specific to your model.

Why your brightness keys might not be working

If you press the brightness keys on your keyboard and nothing happens, the most common cause is an outdated or missing graphics driver. Your graphics driver is the software that lets Windows or Mac communicate with your screen hardware. When it is out of date, brightness controls often stop responding.

On Windows, open Device Manager by pressing Windows key + X and selecting Device Manager. Find Display adapters, right-click on your graphics card (usually Intel, AMD, or NVIDIA), and select Update driver. Choose Search automatically for updated driver software. Windows will check for a newer version and install it if one is found. Restart your computer afterward. On Mac, go to System Settings, click General, then Software Update, and install any available updates.

If updating the driver does not fix it, try restarting your computer. Sometimes the brightness control service straightforward needs to be restarted. If brightness keys still do not work after a restart and a driver update, your keyboard may have a hardware problem, or the brightness control feature may be disabled in your BIOS (a deeper system setting). At that point, using the Settings menu or monitor controls is your reliable workaround.

Reducing eye strain while you brighten your screen

A brighter screen is not always better for your eyes. If your screen is much brighter than the room around it, the contrast can cause eye strain and fatigue. The ideal brightness is usually one that matches the light level of your surroundings — bright enough to see clearly without being noticeably brighter than the space you are in.

Many people find that enabling automatic brightness (adaptive brightness on Windows, automatic brightness on Mac) strikes the right balance throughout the day. If you work in a dim room, a lower brightness setting with good contrast is often more comfortable than maximum brightness. If you work in a bright room or near a window, you may need higher brightness to see the screen clearly. Experiment with your settings over a few days to find what feels comfortable for your eyes.

Troubleshooting brightness that is stuck or unresponsive

If your brightness is stuck at a very low or very high level and you cannot change it, first try the keyboard shortcut or settings menu to confirm the control is truly unresponsive. Then restart your computer — this fixes many temporary glitches with brightness controls.

If brightness is still stuck after a restart, check whether automatic brightness is turned on and whether it is responding to light changes. Try turning automatic brightness off, wait a few seconds, then manually adjust the brightness slider. If the slider moves but the screen does not change, your graphics driver likely needs updating (follow the steps in the section above). If you have an external monitor and its brightness is stuck, check the monitor's physical buttons or menu to see if the control is there instead of on your computer.

Frequently Asked Questions

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

Windows and Mac do not have built-in scheduling for brightness changes, but automatic brightness adjusts based on room light throughout the day. Some third-party apps like f.lux (available on both Windows and Mac) let you schedule color temperature changes, which can reduce eye strain in the evening. These apps work alongside your brightness settings.

Why does my screen get dimmer when I am on battery power?

Both Windows and Mac reduce brightness automatically when running on battery to save power and extend battery life. This is a power-saving feature, not a malfunction. You can override it by manually raising brightness in Settings, but your battery will drain faster. If you want to disable this behavior entirely, go to Power Settings (Windows) or Battery settings (Mac) and look for options related to brightness or power management.

Is a brighter screen better for my eyes?

Not necessarily. A screen that is much brighter than your surroundings causes more eye strain, not less. The best brightness is one that matches your room's light level so your eyes do not have to adjust between the screen and your surroundings. Automatic brightness helps with this by adjusting throughout the day as natural light changes.

What if my laptop screen is too dim even at maximum brightness?

If maximum brightness is still too dim, your screen may be failing or your graphics driver may be limiting brightness. Try updating your graphics driver first. If that does not help, check whether automatic brightness is on — sometimes it overrides your manual setting. If the screen is still too dim after these steps, the display hardware may need replacement, and you should contact your laptop manufacturer or a repair technician.