Why Is My iPhone Changing Brightness On Its Own?
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If you are experiencing an issue with your iPhone changing the brightness on its own, you are not alone, but what is causing the problem?

Why is my iPhone changing the brightness by itself?
Your iPhone is most likely changing the brightness on its own due to ‘Auto-Brigntess’ or ‘Night Shift’ being turned on. To prevent an iPhone from changing the brightness on its own, disable ‘Auto-Brightness’ or ‘Night Shift’ mode in the device settings.
After searching through Apple troubleshooting forums, I have gathered enough information to determine what causes an iPhone to change brightness on its own.
My research has indicated that Apple equips the iPhone with a number of features that automatically change the brightness, which is why users often experience this symptom with their devices.
Why is my iPhone Changing Brightness On Its Own?
The iPhone is one of the most reliable smartphones on the market, and each new model introduces features to improve the user experience. While the majority of these features are intended to simplify using the iPhone, they can often have the opposite effect for some people.
One problem that many iPhone users experience is their screen changing the brightness automatically, which can often feel like your iPhone has a life of its own.
While it can be easy to panic and assume that there is a serious malfunction with your iPhone, odds are this is likely due to the ‘Auto-Brightness’ or ‘Night Shift’ feature being turned on.
What is Auto-Brightness?

Have you ever experienced the annoyance of a bright display in a dark room? Or had to squint your eyes to see the screen on a bright sunny day?
We all have, which is why Apple introduced auto-brightness to the iPhone.
This is an excellent feature that allows the iPhone to automatically adjust the brightness of the display based on the physical lighting conditions of the environment you are in.
If your iPhone is getting darker or brighter on its own, auto-brightness is usually the reason behind it.
What is Night Shift Mode?
We have more screen time in our daily routines than ever before, which can take a toll on our eyes.
Certain colors on an iPhone’s display are particularly damaging to the eyes such as colder blue colors.
Night Shift mode is a feature on the iPhone that essentially works as a blue-light filter, transitioning the display’s colors to become warmer when the sun goes down. This feature can impact the brightness of your iPhone’s screen, and it may cause it to change throughout the day.
How to Fix an iPhone That Keeps Changing Brightness On Its Own
Although many users enjoy the auto brightness and Night Shift mode on their iPhones, these features are not for everyone.
Dealing with a screen that keeps changing its brightness can be tedious and distracting, which is why a lot of people prefer to turn these settings off.

Turning Off Auto-Brightness on an iPhone
When an iPhone starts changing the brightness of its display by itself, the auto-brightness feature is the most likely culprit.
Disabling this feature is one of the first things that a lot of users do when they buy an iPhone, and understandably so. Follow these steps to turn off auto-brightness on an iPhone:
- Open Settings
- Select Accessibility
- Select Display and Text Size
- Scroll down and find ‘Auto-Brightness’
- Toggle auto-brightness into the Off position
Turning Off Night Shift Mode on an iPhone
We’ve known for years that the blue lights on screens are especially damaging to the eyes, which is why Apple features a Night Shift mode on the iPhone.
While Night Shift mode certainly has an appeal, it can also be very annoying to deal with, especially if you want to view your iPhone’s display the way that it’s supposed to look.
If you are tired of dealing with your iPhone changing its brightness automatically, you should consider turning off Night Shift mode to see if the problem goes away.
Follow these steps to turn off Night Shift mode on an iPhone:
- Open Settings
- Select Display & Brightness
- Select Night Shift
- Toggle Night Shift from ‘Scheduled’ into the Off position
If you decide that you want to use Night Shift occasionally on your iPhone, there is a quick way that you can turn this mode back on without having to go through the device’s settings.
Look for a ‘sun’ icon on your iPhone and tap it to turn Night Shift mode back on.
Alternatively, if you want to have Night Shift mode turned on during a different time of day, you can adjust this in the settings. Simply follow the same steps mentioned above to access the iPhone’s Night Shift settings and create a schedule for the feature based on when you want the mode to engage.
How to Change iPhone Brightness Manually
Most users like being in control of their iPhones, which is why they prefer to change settings such as their brightness manually.
This is the go-to approach for many people, and adjusting the brightness manually ensures that you do not have to deal with your display making brightness changes on its own. Try one of these methods to change your iPhone’s brightness manually.
Method 1: Control Center
If you are using an iPhone X or a model that came out afterward, swipe down from the top right corner of the screen. This will open the quick brightness settings of your iPhone so that you can make adjustments as needed without accessing the settings.
If you are using an iPhone 8 or earlier, you will need to swipe up from the bottom of the screen to access these settings.
Method 2: Device Settings
Alternatively, you can change the brightness of your iPhone through the device settings by following these steps:
- Open Settings
- Select Display & Brightness
- Adjust the brightness slider
Key Takeaways
- Your iPhone is changing the brightness on its own due to ‘Auto-Brigntess’ or ‘Night Shift’ being turned on.
- To prevent an iPhone from changing the brightness on its own, disable ‘Auto-Brightness’ or ‘Night Shift’ mode in the device settings.
- You can change the brightness of your iPhone manually by adjusting the brightness slider in the settings or from the control center.