Does dark mode really save battery on a phone?

Question

Weirdo · Accepted Answer

Only on OLED screens, and usually only a little. Purdue researchers found that at typical indoor brightness of 30%–50%, switching from light to dark mode saves only about 3%–9%; at 100% brightness the savings jump to an average of 39%–47%.

On an OLED screen each pixel makes its own light, so dark pixels draw less power. An LCD screen is lit by a backlight that stays on whether the image is black or white, so dark mode barely helps. Purdue notes that most phones released after 2017 likely use OLED, as do iPhones starting with iPhone X. Android's developer docs say the same: dark theme can reduce power use significantly, depending on the device's screen technology.

Purdue's team tested several OLED phones and popular apps. Auto-brightness indoors tends to sit around 30%–40%, where dark mode saves only 3%–9%, too little for most people to notice. Outdoors in bright sun with brightness at 100%, dark mode saves 39%–47%. If battery is the goal, turning brightness down usually does more.

Android lists more benefits than power: better visibility for people with low vision or sensitivity to bright light, and easier use in low-light settings. Turn it on if you like it, just don't expect it to add half a day of battery.

Does dark mode really save battery on a phone?

It depends on whether the screen has a backlight

Brightness matters more than color

There are other reasons to use it