The fastest way to adjust your Mac's screen brightness

You can change your Mac's brightness in seconds using the keyboard shortcut built into every Mac. Press the F1 key to dim the screen and the F2 key to brighten it. Each press moves the brightness up or down by one step. Hold either key down to move through the brightness levels continuously until you reach the level you want.

If your Mac keyboard doesn't have function keys (like on some older or compact models), you may need to hold the fn key while pressing F1 or F2. On MacBook Pro models from 2016 onward, the function keys are replaced by the Touch Bar — a touch-sensitive strip at the top of the keyboard. Swipe left or right on the brightness icon in the Touch Bar to adjust brightness instead.

The brightness change takes effect when ready, and you'll see a brightness meter appear on your screen showing your current level. Once you release the key, the meter disappears after a few seconds.

Key Takeaways

  • Press F1 to dim and F2 to brighten on any Mac keyboard with function keys, or use fn + F1 and fn + F2 if your keyboard requires it.
  • On MacBook Pro models with a Touch Bar, tap the brightness icon and swipe left to dim or right to brighten.
  • You can also adjust brightness through System Settings by opening Apple menu > System Settings > Displays, then dragging the Brightness slider.
  • External monitors connected to your Mac have their own brightness controls on the monitor itself, separate from your Mac's screen brightness.
  • If brightness keys don't work, check System Settings to make sure brightness control is enabled and not locked by parental controls.

Using System Settings to change brightness

If keyboard shortcuts don't work or you prefer a visual control, you can adjust brightness through your Mac's settings. Click the Apple menu in the top-left corner of your screen, then select System Settings (or System Preferences on older macOS versions).

In System Settings, click Displays in the left sidebar. You'll see a Brightness slider in the main panel. Drag the slider to the left to dim your screen or to the right to brighten it. The change happens as you drag, so you can see the effect in real time.

Below the brightness slider, you'll find a checkbox for Automatically adjust brightness. When this is turned on, your Mac uses the built-in light sensor to adjust brightness based on the light in your surroundings. This can help reduce eye strain in different lighting conditions, though you can turn it off if you prefer to control brightness manually.

Understanding brightness on external monitors

If you've connected an external monitor to your Mac, that monitor's brightness is controlled separately from your Mac's built-in screen. The brightness controls on your Mac keyboard or in System Settings only affect your Mac's display, not the external monitor.

To adjust an external monitor's brightness, look for physical buttons on the monitor itself — usually on the bottom or side of the screen. These buttons let you access an on-screen menu where you can find brightness settings. The exact steps vary by monitor brand, so check your monitor's manual if you're unsure where the buttons are or how to use them.

Some higher-end monitors can be controlled through your Mac if they support USB-C or Thunderbolt connection, but most external monitors require manual adjustment using their physical controls.

What to do if brightness keys aren't working

If pressing F1 and F2 doesn't change your brightness, the first step is to check whether brightness control is turned on in System Settings. Open System Settings > Displays and look for the brightness slider. If you can move the slider and see the brightness change, your Mac's brightness control is working — the keyboard shortcut may just need to be re-enabled.

On some Macs, you may need to hold the fn key while pressing F1 or F2. Check your keyboard's function keys to see if they have small icons printed on them (like a sun symbol for brightness). If they do, your keyboard likely requires the fn key.

If brightness still won't change, restart your Mac. Sometimes the brightness control gets stuck after a software update or when switching between multiple displays. After restarting, try the F1 and F2 keys again. If the problem persists, check whether parental controls are restricting changes to display settings — ask the administrator of your Mac to check System Settings > General > Parental Controls if you're not the primary user.

Adjusting brightness for different times of day

macOS includes a feature called Night Shift that reduces blue light from your screen in the evening, which can help reduce eye strain before bed. This is different from brightness — it changes the color temperature of your screen rather than how bright it is. You can use Night Shift alongside brightness adjustment.

To turn on Night Shift, open System Settings > Displays and look for the Night Shift section. You can set it to turn on automatically at sunset and turn off at sunrise, or you can set specific times. You can also adjust the color temperature by dragging the slider from "Less Warm" to "More Warm" depending on your preference.

For the best viewing experience, many people dim their screen brightness slightly in the evening and enable Night Shift. During the day, you may want to increase brightness if you're working near a window or in bright sunlight.

Brightness settings on different Mac models

Most Macs use the same F1 and F2 keyboard shortcuts for brightness, but some older models or specialty keyboards may work differently. MacBook Air and MacBook Pro models from 2016 onward use the Touch Bar instead of physical function keys — swipe on the brightness icon in the Touch Bar to adjust.

iMac and Mac mini users typically use an external keyboard. If your keyboard has function keys with brightness icons, use F1 and F2. If your keyboard doesn't have function keys, you'll need to use System Settings to adjust brightness.

Mac Studio and Mac Pro users connect external displays, which have their own brightness controls on the monitor itself. Your Mac's brightness settings in System Settings won't affect external monitors on these models.

Common mistakes when adjusting brightness

One common mistake is holding down the brightness key too long and overshooting your preferred brightness level. Remember that each press of F1 or F2 moves brightness by one step, so short taps give you more precise control than holding the key down.

Another mistake is confusing brightness with contrast or color settings. If your screen looks dim but the brightness slider is already high, the problem may be with contrast or color calibration instead. Check the other sliders in System Settings > Displays to see if adjusting them helps.

If you have an external monitor connected and you're trying to brighten it using your Mac's keyboard shortcuts, nothing will happen — the monitor's brightness is controlled only by its physical buttons. This isn't a problem with your Mac; it's how external monitors are designed to work.

Frequently Asked Questions

Why does my Mac's brightness keep changing on its own?

Your Mac likely has "Automatically adjust brightness" turned on in System Settings > Displays. This feature uses your Mac's light sensor to match the brightness to your surroundings. If you prefer to control brightness manually, uncheck this box. Your Mac will then keep the brightness level you set until you change it again.

Can I set different brightness levels for different apps?

macOS doesn't have a built-in feature to automatically change brightness based on which app you're using. You'll need to adjust brightness manually when you switch between tasks. Some third-party apps claim to do this, but they're not officially supported by Apple.

Is it bad for my Mac to run at maximum brightness all the time?

Running at maximum brightness uses more battery power on a MacBook and can contribute to eye strain over long periods. Most people find a brightness level between 40 and 70 percent comfortable for indoor work. If you're working outdoors or in very bright light, higher brightness is fine — just lower it again when you move to a dimmer environment.

What's the difference between brightness and Night Shift?

Brightness controls how bright your screen is overall. Night Shift reduces the amount of blue light your screen emits by shifting colors toward the warmer (orange) end of the spectrum. You can use both together — dim your screen and enable Night Shift in the evening for the most comfortable viewing.

Do I need to restart my Mac after changing brightness settings?

No, brightness changes take effect when ready. You don't need to restart your Mac or close any apps. If brightness changes aren't working at all, restarting may help reset the brightness control system, but normal adjustments don't require a restart.