Dark mode turns bright white web pages into dark ones. On many newer phones and laptops, that can cut the power your screen uses, and a free Chrome extension can switch every website to dark mode for you. This article explains when dark mode really saves energy, shares the free extensions the Accessible Sustainability Alliance reviewed, and lists other simple ways to shrink your digital footprint.
Quick answer: Dark mode saves real energy mainly on OLED screens, and the savings are biggest when your screen is bright. A free dark mode extension for Chrome makes every site dark, but lowering brightness and using sleep mode matter just as much.
How dark mode saves energy
Most phones and many newer laptops use OLED screens. On an OLED screen, each tiny pixel makes its own light, and a black pixel is basically off. So a dark page asks the screen to light up fewer pixels. Older LCD screens work differently. They use a backlight that stays on no matter what color is shown, so dark mode saves little or no power on those screens.
A 2021 study from Purdue University measured this on OLED phones. Switching from light mode to dark mode at 100% brightness saved an average of 39% to 47% of battery power. But at 30% to 50% brightness, the savings dropped to only 3% to 9%. The lesson: dark mode helps most if you like a bright screen. Turning brightness down is a strong energy saver on its own.
The free Chrome extensions we reviewed
The Accessible Sustainability Alliance tested more than 100 dark mode extensions for Chrome and other Chrome-based browsers. To earn our seal of approval, an extension had to meet three rules:
- Completely free to use, with no upsell.
- Free of ads, malware and adware.
- Easy to install and uninstall on Chrome-based browsers.
The extensions that made our 2025 recommendation list included:
- Shade Dark Mode
- Dark Mode – Dark Reader for Chrome
- Dark Reader
- Dark Theme – Dark Reader for Chrome
- Night Theme – Dark Mode
- Morpheon Dark
- Gloom Dark Mode
- Umbra Dark Mode
- Dark Mode
- Dark Mode for Web
- Dark Theme for Google Chrome
- Dark Mode for Chrome
- Dark Night Mode
- Turn Off the Lights – Dark Reader for Chrome
Extensions change over time, so check each one before you add it. Look at the permissions it asks for, read recent reviews, and remove any extension you stop using. If an extension owner would like to display our seal, they can email contact@wann.org. There is no charge.
You may not need an extension at all
Chrome has a built-in dark theme. Many websites, including big search and video sites, also have their own dark setting. Your computer’s system setting (dark or light appearance) often tells Chrome and websites which look to use. Try those first. An extension is most useful when you want dark mode on sites that don’t offer it.
Bigger wins for your digital footprint
Dark mode is a small step. Here are a few that often save more:
- Lower your screen brightness. It cuts power on every kind of screen, OLED or LCD.
- Use sleep mode. The U.S. Department of Energy notes that ENERGY STAR estimates power management features can save up to $30 a year on electricity. Screen savers are not energy savers.
- Turn it off. The same DOE guide suggests switching off your computer and monitor if you won’t use them for more than two hours.
- Close tabs and stop autoplay videos you aren’t watching, which keeps your device working less.
Frequently asked questions
Does dark mode really save energy?
Yes, but mostly on OLED screens. Purdue researchers found big savings at full brightness and small savings at normal brightness. On LCD screens, dark mode saves very little because the backlight stays on.
Is dark mode better for your eyes?
Many people find dark mode more comfortable at night or in dim rooms. Others find light text on a dark background harder to read in bright rooms. Pick what feels comfortable, and keep brightness at a level that matches your room.
Are dark mode Chrome extensions safe?
Many are, but any extension that changes every website needs permission to read and change those pages. Install only well-reviewed extensions, check their permissions, and remove the ones you no longer use.
See your home energy impact
Screens are only one part of your home’s electricity use. Try our free Home Energy Simulator to see how lighting, appliances, heating and cooling add up, and which changes save your household the most.
Related guides
- How to Use a Free Weather App to Time Your Energy Use
- How to Set Up an Offline Smart Thermostat You Actually Own
- How to Build a DIY Smart Home Hub with Open-Source Software
Sources
- Purdue University, Dark mode may not save your phone’s battery life as much as you think, but there are a few silver linings
- U.S. Department of Energy, Energy Efficient Computers, Home Office Equipment, and Electronics
Written and reviewed by the Accessible Sustainability Alliance editorial team. Last updated October 5, 2026.
