Dark Mode on the iPhone can save massive amounts of battery life, test shows

If you're sick of hearing about dark mode on smartphone apps, I hear you. Now that both Android and iOS have the option to turn your interface darker, not a day goes by without this or that app adding support for dark mode.

But beyond aesthetics, there's a real-world reason to turn on dark mode: increased battery life. According to a recent test, conducted by PhoneBuff, switching to dark mode can extend your iPhone's battery life by 30 percent.

In the test, identical tasks were performed on an iPhone XS Max in Twitter, YouTube, Message, and other apps, first with the phone running light mode, and then with dark mode on.

The result is quite spectacular. When the battery on the iPhone running light mode died, the other iPhone still had 30 percent battery life, which should give you several extra hours of aimlessly scrolling through your Twitter feed performing important work tasks. For comparison, Apple says the iPhone XS Max's battery will last for 15 hours of video playback, while the battery on the iPhone 11 Pro Max can do 20 hours — a 33 percent increase.

Things aren't that simple, though. The test phones were set to 200 nits of brightness; you might see different results with other settings. Furthermore, during the test a single app was used for several hours at a time, which is (hopefully) not how most users use their phones.

And there's a one big caveat: Only smartphones with OLED screens will see the battery life improvement, as OLEDs expend less energy when the screen is dark. A phone with an LCD screen, such as the iPhone 11 or the iPhone XR, would likely get no benefit.

Still, this should motivate users to at least try dark mode on their OLED phones. If you can get used to it, you might get a significant battery boost as well, and this boost should increase as more popular apps add support for dark mode (we're waiting for you, Facebook).