Does Using Dark Mode On Your Phone Significantly Improve Battery Life

Using dark mode on your phone has been touted as a way to extend battery life, but the actual benefits are more nuanced than often claimed. Here’s a detailed look at how dark mode impacts battery life, based on recent research from Purdue University.

How Dark Mode Affects Battery Life

The study by Purdue University researchers, led by Charlie Hu and Pranab Dash, aimed to accurately measure the power draw of OLED displays in various brightness settings. They tested six popular Google apps, Calculator, Google Calendar, Google Maps, Google News, Google Phone, and YouTube, on several Android smartphones with OLED screens, including the Pixel 2, Moto Z3, Pixel 4, and Pixel 5.

Brightness Levels and Power Savings

The key findings indicate that the power savings from using dark mode are highly dependent on the screen brightness:

At 30%-50% Brightness: Switching from light mode to dark mode saves only between 3% and 9% power on average. This range is typical for auto-brightness settings, which most users employ.
At 100% Brightness: The savings are significantly higher, with an average reduction in power consumption of 39% to 47%. This is particularly relevant for users who need high brightness, such as in outdoor conditions.

OLED vs. LCD Displays

The difference in power consumption between dark and light modes is primarily relevant for OLED (organic light-emitting diode) displays. Unlike LCD (liquid crystal display) screens, which require an external backlight, OLED displays create pixels without an external light source. This means that darker pixels draw less power, making dark mode more energy-efficient on OLED screens.

Practical Implications

For most users, the 3% to 9% power savings at average brightness levels may not be noticeable in daily use. However, there are scenarios where dark mode can make a significant difference:

Outdoor Use: If you frequently use your phone in bright sunlight and need to set the screen to maximum brightness, switching to dark mode can save up to 47% of battery power.
Eye Comfort: Even if the battery savings are minimal, dark mode can reduce glare and protect your vision, especially in dimly lit environments.

Tools for Accurate Measurement

The Purdue researchers developed two tools to help measure and manage power consumption more accurately:

FPOP (Per-Frame OLED Power Profiler): This tool allows app designers to study how user interface settings, such as dark mode, impact power draw in real-time.
Android Battery+: This enhanced version of the native Android battery utility takes into account the content displayed on the screen, providing a more accurate picture of energy consumption.

Real-World Examples

The study also highlighted some interesting real-world examples:

Google News App: On the Pixel 5, using the Google News app in light mode at 20% brightness draws the same amount of power as using it in dark mode at 50% brightness. This suggests that increasing brightness in dark mode does not significantly increase power consumption.

Conclusion

While dark mode does offer some battery life benefits, these are generally modest unless you are using your phone at high brightness levels. For most users, the primary advantages of dark mode lie in its comfort and readability benefits rather than significant battery life extensions. However, with the development of new tools to measure and optimize power consumption, app developers can create more energy-efficient apps, which may lead to greater overall battery life improvements in the future.