Samsung Galaxy screen brightness keeps changing? 5 causes

By Saadat Rafiq · 2 min read · 5 steps · Updated 5 October 2026 · ▶ Video demo

Device

Android

Shown on

Samsung Galaxy A57 5G (SM-A576B), One UI 8.5, Android 16

App

Settings

Real screenshots

4 of 5 steps

Checked

October 2026

Sources

2 official, linked below

Step by step

1. 

   Open Display

   Open Settings and tap Display.

   Done

2. 

   Switch off Adaptive brightness

   It was on on our phone. Off, the brightness stays where you set the slider above it. It can also be switched from the quick panel.

   Done

3. 

   Set the level yourself

   Drag the Brightness slider. Samsung notes a prompt to turn Adaptive brightness back on may appear once after a restart if you set it above 90%.

   Done

4. 

   Check Power saving

   Settings, Battery, Power saving lowers brightness to save battery.

   Done

5. Let a hot phone cool down

   The phone dims itself when it overheats, for example in the sun, while charging or gaming, or when the battery is critically low. This is protection, not a fault.

   Done

About this guide

Samsung says the brightness follows the surrounding light, the phone's temperature and the battery level. Only the first is a setting you can switch off.

The screenshots are from a Samsung Galaxy A57 5G with One UI 8.5 and Android 16. Other Galaxy phones on One UI 8 use the same menus; on older One UI versions a few names and positions differ. We only looked at these screens on our phone and changed nothing.

Good to know

Eye comfort shield makes the screen warmer and yellower, which can look darker. It was off on ours: how to turn on Eye comfort shield on a Samsung Galaxy phone.

Even darker than the lowest setting? How to use Extra dim on a Samsung Galaxy phone.

In short: Display, Adaptive brightness off, set the slider. Power saving, heat and a low battery also dim the screen.