Does dark mode make batteries last longer?


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Dark mode is often recommended as a way to conserve battery life on devices like smartphones, tablets, and laptops. But can it really boost your mobile device’s battery backup? Here is everything you need to know.

What is dark mode?

Before we talk about the impact of dark mode on your device’s battery life, it’s a good idea to understand it.

Dark mode, also known as dark theme, is a display setting on many devices that changes the background color of the system and its applications from a light color to black or dark gray and makes text appear in a light color, usually white.

It potentially has several benefits, including reducing power consumption and making your device’s battery last longer. However, it’s not as simple as turning on dark mode and hoping that the battery life increases a few hours.

The impact of dark mode on a device’s battery life depends on two key factors: the display technology used on your device and the system background color when dark mode is enabled. So let’s start with the display technology.

Display technologies and dark mode

AR Emoji on the phone.
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Virtually all modern mobile devices with screens use one of two main display technologies: OLED and LCD.

OLED or organic light-emitting diode displays have self-emissive pixels, which means that the pixels in an OLED display can produce their own light when an electrical current is passed through them. Therefore, they do not need a backlight to create images and text. This also means that when an OLED screen has to produce the color black, it simply turns off the pixels in the required part of the screen and you get a completely black color.

So when you enable dark mode on a device that has an OLED screen, be it a phone, tablet, or laptop, the device must feed a relatively smaller number of pixels as long as the background or parts of it are completely black. As a result, you consume less power and your device’s battery lasts longer. However, the impact on battery life will depend on how often parts of your device’s screen are completely black.

Person using a laptop in a coffee shop
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On the other hand, LCD or liquid crystal displays need a backlight, usually LED or mini-LED, to illuminate the pixels and produce images and text. So when an LCD screen has to create a black color, it tries to block the backlight in the areas of the screen where black is needed. However, even when it displays black, the LEDs are still on and the display stack can’t completely block the light. As a result, some light escapes and the blacks on most LCD screens appear gray.

However, LCD screens have come a long way in recent years and we now have technologies like local dimming and Mini-LED. Both offer better backlight control, resulting in significantly better black levels. Therefore, a display that uses LCD technology with Mini-LED backlighting and full-array local dimming (FALD) may turn off some of the LEDs when it needs to display black.

Therefore, using dark mode on devices with an LCD screen may also result in some power conservation, as it supports full-array local dimming and Mini-LED backlighting, as the screen will not use all of the LEDs. when the background is black. That said, local dimming and Mini-LED backlighting are relatively uncommon on mobile devices. You’ll only find these technologies on select laptop and iPad Pro models. And energy savings will depend on the number of dimming zones, the local dimming algorithm, and the size of a zone.

RELATED: This is when a dark theme can save battery power

background color matters

apple ipad mini

In addition to display technology, the background color used by a platform or app while dark mode is enabled can determine whether you’ll see any benefit on the battery front. As mentioned, all OLED devices can turn off pixels, and some LCD devices can dim part of their backlight to display black. This helps conserve power and prolongs a device’s battery life.

However, this is only possible when the background elements are actually black and not a shade of gray. But sadly, many platforms, devices, and services use a dark gray background, rather than black, for aesthetic reasons. Therefore, the extent of battery life savings with dark mode may vary.

How much power savings can you expect with dark mode?

The amount of power savings you can expect from using dark mode depends a lot on how bright your device is. This is because the higher the brightness level of your phone or laptop, the faster the battery will drain.

According to a 2021 study by Purdue University, if you keep your OLED phone’s brightness level between 30% and 50%, you can expect only 3% to 9% energy savings. However, if your phone is always at 100% brightness, dark mode will save 39-47% of your battery. You’ll likely get similar results on OLED tablets and laptops.

FALD and Mini-LED backlit LCD devices are likely to be less power efficient than OLED devices as their backlight control is not at the pixel level. Therefore, they will have less chance to dim the LEDs and save energy.

Better battery life but with caveats

All in all, dark mode can make batteries last longer. But there are plenty of caveats. It is most useful for people with a phone, tablet, or laptop with an OLED screen. But even then, your device platforms and apps should have a black background in dark mode and not a gray version. Otherwise, you won’t see any benefit even with an OLED screen. Most LCD users are out of luck, unless you have a mobile device that uses local dimming and Mini-LED backlighting, which is rare. And finally, let’s not forget about the brightness of the device.

If you’re concerned about the health of your smartphone’s battery, check out our list of ways it could be ruining your battery.

RELATED: 4 ways to ruin your smartphone battery