Does Dark Mode Really Save Battery on Your Phone?
Wie Tech funktioniert

Does Dark Mode Really Save Battery on Your Phone?

At WWDC today, iOS 13 was shown with a system-wide “Dark Mode.” About one month earlier, at Google I/O, Android version Q showed off its own Dark Mode. This shift to the dark side is seemingly happening everywhere. But not every device gets a battery-saving boost from dark mode.

If your phone has an OLED display, turning on dark mode is like turning off a bunch of lights in your house, and the net power gains add up over time. But not all “dark” modes are the same.

How Dark Mode Works on OLED Screens

Sub-pixels on an OLED display
Green, red, blue, green, red, green, blue.

The hardware explanation for the sudden uptick in dark interfaces is that newer OLED screens light up differently than traditional LCD screens. Each OLED pixel generates its own light, while LCD screens light all pixels from the edges. OLED pixels that are black draw no power, and are closer to pitch-black than LCD screens, which draw the same amount of power whether they’re displaying an all-white image or an all-black one. So if you have a fully black wallpaper on your OLED phone, it’ll only light up the pixels it needs to create the icons and text, while leaving the background pixels off entirely.

But in their zeal to promote the dark side, some articles don’t make an important thing clear: dark mode will not save you any battery power if you’re using an LCD screen.

Not sure if your phone has an OLED display? The iPhone X, XS, and XS Max use OLED screens, while the iPhone XR, and every iPhone before the X, use LCD. Most newer Samsung phones, particularly the Galaxy S and Note series, use OLED, as do most of the firm’s devices of the past 3 years. It’s easy enough to search for any device on iFixit and look for the “Display” category under Specifications.

How Much Difference Does Dark Mode Make?

Google presentation slide showing 60% difference in battery usage on YouTube, black versus white modes
Image via Google / SlashGear

Each OLED pixel is just one tiny light, but for those who use their phone for long periods (more of us than we’d like to admit), those thousands of little pixels add up over the hours.

Google’s engineers calculated a 63 percent drop in screen power use between a Pixel phone showing a screenshot of Google Maps in normal mode versus dark mode. Ryan Whitwam did his own dark mode tests at Greenbot in 2014 and saw a 41 percent drop in battery draw when reading Reddit in dark mode. AppleInsider measured 60 percent battery savings. In real-world use, that’s about an hour of extra battery life per day, depending on a few factors. That’s nothing to sneeze at. The more battery life your phone gets, the less often you have to charge it, and so the less frequently you’ll have to buy a new battery.

How to Enable Dark Mode on Your Phone, Tablet, or Laptop

Mac computers with dark mode enabled

The easiest way to enable OLED-friendly dark modes is to look in the settings of the applications you use most often, or for the longest stretches of time. Social media apps like Twitter, Facebook Messenger, many Google apps, and most apps meant for reading (Reddit, Pocket, Kindle) offer a dark mode. The Verge is keeping an ongoing tally of apps going dark, too.

System-wide dark modes are available in Windows 10 and MacOS Mojave (though scant few laptops, and no MacBooks, use OLED screens). iOS 11 and 12 have a “Smart Invert” mode that is close to a true “dark mode,” and iOS 13 will have a dark mode. Android Q will have a system-wide dark mode, and some alternative home screen launchers, like Nova Launcher, can get you halfway there. In general, searching the name of the app or device and “dark mode” should reveal the answer and the method to enabling dark mode.

Android owners, however, must be extra cautious about installing any extra extensions, apps, skins/themes, or other add-ons, especially from companies that didn’t make the device or software. Third-party dark modes are often awkward and compromised solutions, at best, and could harbor annoying or malicious ads or spyware at worst.

What Other Benefits Are There to Dark Mode?

Google Calendar on mobile set to Dark Mode

Besides saving you power, there are also subjective benefits of using dark mode apps. Turning on your phone in the dark can be startling to you, and annoying to people nearby, especially when looking at white webpages or all-white Google apps. If you’re going to stare at a phone in a dark room, it can feel less fatiguing to look at a mostly-dark screen. None of this absolves you of looking at a phone in a theater, by the way―don’t do that.

The third benefit of dark mode is aesthetics, and it can work one of two ways. Some people prefer the look of white text on a dark background (our engineering team and John Gruber among them). But what about those who prefer a modern, white-background look to a somewhat more 1990’s-evoking black canvas with brightly colored buttons? Dark mode is a choice, and almost never the default for an app or device, so you can avoid it entirely.

But consider that making your phone less appealing to look at can be a strategic way of using it less. You can go even further: turn on grayscale mode, disable fingerprint locking and give your phone a more serious unlock password instead of a numeric code. Dark pixels on an OLED screen save you battery power, but a screen that’s off saves the most.

Top image by Daniel Korpai on Unsplash