Google has finally confirmed that dark mode does indeed save battery on Android smartphones. This is something that was known by pretty much everyone, and it makes a ton of sense. Google even released a graph that shows battery usage for apps that are all dark versus those that are white (like much of Google's apps are), and there is a huge difference in battery usage there. The easiest way to explain why there is such a big difference is that with dark mode, especially all black modes, there are less pixels that need to be lit. This is particularly true on OLED displays since every pixel is lit individually. And when you have a ton of white space, that's a lot of pixels that need to be lit, and that translates into poor battery life. Now as you can see from the graph below, that is a decent change between black and white, but even red and green are pretty low.
Android used to be completely dark, the entire OS. But over the years as Google has adopted Material Design, it has instead gone to a lighter interface, which not everyone is excited about. The reason for this was due to the design guidelines that Google had outlines for Android and apps. But, many did not like it being so bright, since we do use our smartphones at night, when it's dark. And using a white interface can be pretty blinding. And now that Google knows, and admits, that dark mode is better for battery life, it wouldn't be a big surprise to see Google adding dark mode to more of its apps, and even system-wide in Android Q next year. We do have dark mode on the notification shade and the app drawer, but the rest of the operating system is white or light gray. That will likely change, in the next major Android update or two.
In the picture below, you can see how much of a difference the dark mode on YouTube is making. It shows that at 50-percent brightness, it's only a 14-percent difference, between dark and normal mode. That's not a big difference, but it does make a difference. Now at 100-percent brightness, it's a much bigger gap, of around 60-percent. And what is perhaps even more interesting here is that normal mode at 50-percent brightness is 93mA, while dark mode at 100-percent brightness is 96mA, showing that white mode at 50-percent brightness is almost the same as dark mode at full brightness. That is pretty insane, and a huge difference. So if you're serious about saving battery, dark mode on YouTube is definitely worth toggling on.
Background: Dark Mode has been a favorite of many Android enthusiasts, not just because it is darker and saves battery life, but it also looks better. Many of Google's partners have been going dark on its skins for different devices. Like Huawei, for instance, was already dark, but it has now added a truly black theme for devices with an OLED display, like the P20 Pro and Mate 20 Pro. That helps save battery life, rather significantly on an OLED panel, because it is lighting up those pixels individually, so the less pixels you need to light up, the less power is being used. Which is always a good thing with smartphones, especially those that have smaller batteries, or might be a bit older.
In the past few months, there have been plenty of leaks from Google with their apps turning to dark mode. Some of these were from teams that were "dogfooding" the app (this is how Google tests apps and features internally before rolling them out) that were sent out to people outside of Google by mistake. But so far, really only Google News has added a dark theme, which looks really good on the news app. Google isn't forcing everyone to use the dark mode either, it is offering up the light mode and dark mode and it can change automatically based on the time of day. So after sunset it'll change to dark mode and during the day it is light. But you can also opt to change it to dark mode all the time, or only switch to dark mode when in battery saver mode - which that right there shows that Google knew that dark mode was better on battery than light colors. So we do know that Google's teams are working on dark modes for different apps from Google. But so far, only a couple have dark modes available, like YouTube and Google News. But others should be rolling out their dark modes rather soon.
Impact: This is going to have a rather big impact on Android in the future. Dark mode is something that everyone has been asking for, for quite some time. Not only is it going to provide a better user experience for users, but it is also going to provide better battery life. And this is something that Google can do without having to limit how fast processors are going during battery saver mode, or limiting data connections, or even adding a larger capacity battery. Now yes, it's not going to double your battery life - though that chart does say something different - but it is going to be a noticeable difference. If you have a smartphone with an OLED display (like the Samsung Galaxy Note 9, LG V40 ThinQ or Google Pixel 3) and use a black background on that phone, you will really notice the difference in battery life. It's actually pretty significant. Now imagine that throughout your entire phone, that can be an even more significant savings.
There are other, non-Google apps out there that do have dark modes, like Twitter. And while it isn't a black or even dark gray mode, it is a dark blue, which uses a tad more energy than a true black theme would use, but it is far better than using the default white mode on Twitter. Google is now urging developers to use dark mode, or at least give users a choice. They aren't forcing everyone to move to a dark mode on their app, but they do at least want users to have the choice. Of course, most users will opt for a dark mode anyways. And this isn't really because of battery life, but because users do use their phone a lot in bed, and a dark mode is easier on the eyes than a white or light mode.