Dark mode
Also known as: dark theme, dark mode setting
Dark mode is a display setting that switches apps and operating systems to light text on dark backgrounds instead of the usual dark text on white.
Many people find it more comfortable at night or in dim rooms, and on OLED screens it can save battery because dark pixels use less power. While dark mode is popular, research doesn't show it's better for eye health overall, and some people with astigmatism find light text on dark backgrounds harder to read.
Dark mode, explained at three levels
At home
Dark mode is like dimming the lights in a room at night. Screens show dark backgrounds instead of bright white, which many people find more comfortable.
At work
Offering dark mode in apps and websites improves comfort for staff and customers who prefer it.
At home
You can set dark mode to switch on automatically at sunset in your phone or computer's display settings. Many apps follow the system setting.
At work
Websites can detect a user's dark mode preference with the CSS prefers-color-scheme feature. Designs should keep strong contrast in both modes for accessibility.
At home
Dark mode saves battery mainly on OLED screens and at higher brightness. In my opinion, use it because you like it, not because you expect big battery gains.
At work
Design and test both themes, check contrast ratios against accessibility guidelines, and avoid pure black backgrounds with pure white text, which can cause visual 'halation' for some users.
Real-world examples
At home
Sophie reads on her phone in bed. Switching on dark mode made the screen feel less harsh at night.
At work
Carlos leads design for a Toronto banking app. His team added dark mode and tested contrast carefully so text stayed readable for users with low vision.
How it compares
| feature | Dark mode | Light mode |
|---|---|---|
| Background | Dark | Light |
| Best in | Dim rooms, night | Bright rooms, daytime |
| Battery on OLED | Saves some power | Uses more |
| Readability of long text | Varies by person | Often easier |
Dark mode is a comfort choice, not a health requirement.
For analysts
When users request dark mode, I'd include accessibility contrast checks in the requirements. A poorly designed dark theme can be less accessible than light mode.
History & origin
Early computer screens showed green, amber, or white text on black backgrounds, because that's what the technology did best. Graphical interfaces such as the Macintosh in 1984 and Windows popularized dark text on white, mimicking paper. Dark themes survived among programmers in code editors. Windows 10 added a system-wide dark theme in 2016, macOS Mojave brought dark mode in 2018, and iOS 13 and Android 10 followed in 2019. Google said in 2018 that dark mode could save significant power on OLED screens at high brightness, while a 2021 Purdue University study found more modest savings at typical brightness. In my view, dark mode is about comfort and choice more than health.