According to our figures, enabling dark mode on your phone can save up to 60% on battery power.
Google did a series of tests between Pixel (Galaxy S, Samsung Note, iPhone X, OLED screen like XS and XS Max, iPhone 7 with LCD). If you change the Google Maps interface to night mode, the Pixel's battery will consume 63% less power than it currently does, while iPhone has not changed any of its consumption.
This happens because there is an LED backlight on the LCD screen and the OLED screen illuminates the individual pixels. In an OLED panel, each pixel has red, blue, and green light: to display black, the pixel turns off all three lights. To show white, brighten them.
This means that the OLED screen consumes less black and consumes more white. And the application uses more white. This is a mistake made by the trend to introduce a new dark mode as an option (try YouTube 9, Twitter, Reddit, and Android 9 at the global level of the system).
All of these tests were performed with maximized screen brightness. If the brightness of the screen is reduced by half, the saving effect is only 14%. Even the dark mode interface usually uses gray and blue tones instead of black. They consume more, but OLEDs take slightly longer to change color when coming from black. So in some cases, like white text with a black background, there is a delay when the phone scrolls.