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Why Does My iPhone Brightness Keep Changing or Dimming?

Have you been struggling with a display that keeps dimming despite your attempts to turn the screen brightness up? There are several possible causes for this problem, many of which can be easily fixed if you know what to look for!

In this article, find out why your iPhone’s brightness keeps changing and how to stop it from happening.

iPhone features that can affect brightness

If you find that your iPhone brightness keeps changing or dimming unexpectedly, don’t panic! It doesn’t necessarily mean that there’s something wrong with your phone. There are a variety of features that can affect screen brightness. It’s a good idea to check them all before jumping to conclusions.


Generally, if your iPhone screen keeps dimming, it’s because Auto-Brightness is turned on. This feature automatically adjusts the brightness of your phone screen based on the surrounding lighting.

If you want to stop your phone from dimming automatically due to this feature, go to Settings –> Accessibility –> Display & Text Size and toggle off Auto-Brightness. You’ll see a warning that turning off Auto-Brightness can affect battery life. This is because leaving your phone on maximum brightness all day will drain the battery faster than allowing it to adjust automatically to the ambient light.

Night Shift

If your iPhone screen seems dimmer at night, it may be because you have Night Shift turned on. This feature shifts to warmer tones after sunset (using the clock and geolocation of your phone to ascertain when the sun will set) to help you fall asleep.

Go to Settings –> Display & Brightness –> Night Shift. There, you’ll be able to adjust the settings or turn Night Shift off entirely. You can also turn Night Shift on or off from the Control Center if your iPhone is running iOS 11 or later. Open Control Center by swiping down from the upper right-hand corner if your phone has Face ID, or swiping up from the bottom of your screen if not. Simply press and hold the brightness slider in the Control Center to access the Night Shift button.

True Tone

True Tone is a feature that automatically adjusts the colour of your phone’s display based on the ambient light, just like Auto-Brightness does for screen brightness. The colour shift may sometimes make your screen appear dimmer. Go to Settings –> Display & Brightness and check to see whether True Tone is on!

Low Power Mode

Low Power Mode is a feature that adjusts a variety of settings, including screen brightness, in order to conserve battery life. You can easily check whether your iPhone is in Low Power Mode by taking a look at the battery icon in the top right-hand corner. If it’s yellow, that means that Low Power Mode is on.

Low Power Mode will automatically turn off when your iPhone is charged to 80% or more, but if you’d like to turn it off manually, go to Settings –> Battery and toggle it off.

Reduce White Point

Reduce White Point is a feature that lowers the intensity of bright colours on your screen, making the display easier on the eyes. Go to Settings –> Accessibility –> Display & Text Size to access Reduce White Point. If you don’t want to turn it off completely, you can drag the slider further to the left to lessen its effect.

Common iPhone problems that can affect screen brightness

If none of the features listed above are causing your screen dimming problem, your iPhone may be experiencing a software or hardware issue. If that’s the case, there are a few simple fixes you can try before taking your phone to a professional for repair. If none of these solutions work, it may be a sign that you need a new phone.

Software glitches

Whenever we’re having trouble with a device, the first piece of advice we usually hear is “try turning it off and on again.” While it may seem silly, a simple restart can actually resolve many common phone problems! Your screen brightness issues may be caused by a temporary glitch that can be resolved by restarting your iPhone.

If that doesn’t work, try updating your phone. If a software glitch is the culprit, there may be a fix for it in the latest update.


iPhones are programmed to dim automatically when they get too hot. This is a built-in feature from Apple that is designed to protect the phone’s internal components and prevent hardware damage, because the brighter a display is, the more heat it generates.

If your phone is getting too hot, it’s important to cool it down and figure out why it’s overheating. Possible causes include running power-intensive apps like mobile games or video players, having too many apps running in the background, downloads and installations and leaving your phone out in the sun. Try putting your phone in a cool place out of the sun, taking off the case and letting it rest for a while. You can even turn it off to try to speed up the cooling process.

Need to replace your iPhone? Shop at Recycell!

If you’ve tried everything on this list and still haven’t found a solution for your screen dimming problem, it may be a sign that something more serious is wrong with your phone. You may end up needing to have it repaired or replace it entirely.

Getting a replacement iPhone can be a very expensive prospect, but it doesn’t have to be! You can find a used phone online that’s still in great condition and costs far less than a brand-new device. Recycell offers a wide range of used smartphones and cell phones at unbeatable prices. Get a great replacement today!


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