What Is Dark Mode?

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

Dark mode, also referred to as dark theme, is a display setting on many devices that switches the background color of the system and its apps from a light color to black or dark grey and makes the text appear in a light color, typically 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 the dark mode and expecting the battery life to go up by a few hours.

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

Screen Technologies and Dark Mode

Pretty much all modern mobile devices with a screen utilize one of two major display technologies—OLED and LCD.

OLED or organic light-emitting diode screens have self-emissive pixels, which means the pixels on an OLED screen can produce their own light when an electric current is passed through them. So they don’t need a backlight to create pictures and text. This also means when an OLED screen has to produce the black color, it simply turns off 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 has to power a relatively fewer number of pixels whenever the background or parts of it are entirely black. As a result, it takes less power, and your device’s battery lasts longer. However, the impact on the battery life will depend on how often parts of your device’s screen are completely black.

On the other hand, LCDs or liquid crystal displays need a backlight, typically LEDs or Mini-LEDs, to illuminate the pixels to produce pictures and texts. So when an LCD has to create black color, it attempts to block the backlight in areas of the screen where black is needed. However, even when it’s displaying the black color, the LEDs are still lit up, and the display stack is unable to block the light completely. As a result, some light escapes, and the blacks on most LCDs appear grey.

However, LCDs have come a long way in the last few years, and we now have technologies like local dimming and Mini-LED. Both of these offer better backlight control, resulting in significantly better black levels. So a screen using LCD technology with Mini-LED backlighting and full-array local dimming (FALD) can switch off some of the LEDs when it needs to show black color.

So using dark mode on devices with an LCD can also result in some power conservation, given there is support for full-array local dimming and Mini-LED backlighting, as the display won’t use all LEDs when the background is black. That said, local dimming and Mini-LED backlighting are relatively uncommon on mobile devices. You will only find these technologies in select laptops and iPad Pro models. And the power savings will depend on the number of dimming zones, the local dimming algorithm, and the size of a zone.

RELATED: Here’s When a Dark Theme Can Save Battery Power

Background Color Matters

Apart from the screen technology, the background color used by a platform or app while the dark mode is enabled can dictate if you will see any benefit on the battery front. As mentioned, all OLED devices can switch off the pixels, and some LCD devices can dim part of their backlighting to display the black color. This helps conserve power and prolongs the battery life of a device.

However, it’s only possible when the background elements are actually black and not a shade of grey. But unfortunately, many platforms, devices, and services use a dark grey background, instead of black, for aesthetic reasons. So the extent of battery life savings with the dark mode can vary.

How Much Power Savings Can You Expect With Dark Mode?

The amount of power savings you can expect by using dark mode depends a lot on the brightness of your device. This is because the higher the brightness level of your phone or laptop, the quicker its battery will deplete.

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

LCD devices with FALD and Mini-LED backlighting are likely to see worse power savings than OLED devices as their backlight control is not pixel-level. So they will have fewer chances to dim the LEDs and save power.

Better Battery Life But With Caveats

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

If you’re concerned for your smartphone battery’s health, check out our list of ways you might be ruining your battery.

RELATED: 4 Ways to Ruin Your Smartphone’s Battery