Display and appearance
Auto-Brightness
Most people call this the screen brightening and dimming on its own.
The ambient light sensor raises and lowers screen brightness to match your surroundings, and the switch lives under Accessibility rather than Display.
This setting is present on your iPhone.
- We have this path on file but have not yet confirmed it against an official source.
Where to find it - iOS 11 and later
- Settings
- Accessibility
- Display & Text Size
- Auto-Brightness
What it does
Brightness tracks the light around you, and the phone also learns from manual adjustments you make in similar conditions. Turning it off fixes brightness at whatever you last set, until heat or Low Power Mode intervenes.
What changes
When it is on
Brightness changes automatically as light changes.
When it is off
Brightness stays where you put it, which often means too dark outdoors and too bright at night.
Should you turn it on?
Good reasons to turn it on
- The screen stays readable everywhere without thought.
- It saves battery by dimming in dark rooms.
Good reasons to turn it off
- You want predictable brightness for editing or video.
- The automatic changes feel like the phone overriding you.
Battery
Helps
Privacy
No real change
Performance
No real change
Cellular data
No real change
Storage
No real change
Out of the box: On.
Where this setting used to live
Apple moves settings between releases. This is every location we have on file.
-
iOS 11 and later
Settings > Accessibility > Display & Text Size > Auto-Brightness
-
iOS 5 to iOS 10
Settings > Display & Brightness > Auto-Brightness
Questions people actually ask
- Why does my iPhone brightness keep changing?
- Auto-Brightness is responding to the light around you, or the phone is warm and protecting itself.
- Where is Auto-Brightness?
- Settings, then Accessibility, then Display and Text Size. Apple moved it out of Display and Brightness in iOS 11.
If it is not working
- The switch is under Accessibility, then Display and Text Size, not under Display and Brightness.
- Brightness also drops when the phone is hot, and that cannot be turned off.
- Cover and uncover the sensor near the earpiece to check it is not blocked by a case or screen protector.