Dark Mode

At the 2018 Android Dev Summit, Google discussed how the choice of colors in Android applications directly affect battery life. This confirmed the obvious — Dark Mode can significantly help reduce the battery drain on devices with OLED screens. The rationale is that pixels are completely turned off, unlike LCD screens where power is required to display both light and dark shades of a pixel. Additionally, users are also asking for platform support for usability and ergonomic reasons: Dark Mode is easier on the eyes, especially at night!

While Dark Mode may help reduce battery drain attributed to the display, the exact energy savings are highly dependent on the display content. Despite the surge of many popular apps adding support for Dark Mode this past year (Google Maps, Gboard, FB Messenger and YouTube to name a few), it remains unclear how much battery Dark Mode will actually save. Answering this question is crucial to help app designers make informed design decisions and to justify the development effort of implementing Dark Mode. The end goal ultimately being to increase mobile revenue from prolonged user engagement due to battery savings.

That's according to the source I found on the internet. But to my own experience and from the reviews I have seen online, Dark Mode can really reduce battery drain faster. Many users are recommending this feature at night or it's up to the user.

If your phone uses OLED display, yes! Dark mode helps save battery by the black pixels as "turned off", so no pixels are "illuminated". This video may help: https://youtu.be/qbxdHpD5jWw