Fact vs. Myth: Does Dark Mode Really Save Your Phone’s Battery Life?

Dark mode is one of the coolest options you can experiment with in your smartphone device. App builders work very hard to bring their UI/UX features in dark mode. This works on the concept of ‘color inversion’, which means your media assets would be rendered as is against a black background. There are many benefits of using Dark Mode, one of them being legibility. Some also believe that using of color inversion properties can cut glare and protect your vision against blue rays. But how many of you actually believed that using dark mode can save your phone’s battery life? Honestly, I didn’t. And, I asked a few of my colleagues and friends– they were just as clueless. What do you think? Is it a myth or a fact?

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To answer this effect of dark mode on battery life, Purdue University researchers conducted a scientific study. According to the study, dark mode doesn’t necessarily save much battery life. But hey! There’s more to dark mode  features than just saving vision, improved quality of images, improved legibility, or just battery life.

Why Are We Even Discussing Dark Mode Here, Eh?

Both Google’s Android and Apple’s iOS provide Dark Mode and advanced updates for a better screen experience. It is mostly used in dimly-lit ambiance or at night. In the initial phase of its arrival, both Android and Apple updates carried a feature that showed device’s potential for saving battery life with Dark Mode: ON. Logic would suggest that darker-colored pixels would lesser power compared to lighter-colored pixels.

But, Purdue found that change in mode hardly makes any big difference to battery life with the way that most people use their phones on a daily basis.

But, dark mode: ON has its benefits. Charlie Hu, Purdue’s Michael and Katherine Birck Professor of Electrical and Computer Engineering says, “When the industry rushed to adopt dark mode, it didn’t have the tools yet to accurately measure power draw by the pixels. But now we’re able to give developers the tools they need to give users more energy-efficient apps.”

The work will be featured at MobiSys 2021, a conference by the Association for Computing Machinery.

What the Study Found About the Link Between Screen Mode and Battery Life

Mobile app development and mobile computing are advancing at a rapid pace. We are seeing a massive push to the research areas in Mobile Computing, OLED design, and Power and Energy optimization, all linked to usefulness of a smartphone device in the era of 5G, IoT and human-centered experience management. It makes sense to understand the impact of switching between On-Off Dark Mode on device’s battery performance.

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Based on recent findings, Purdue researchers are recommending newer ways to users who possibly could take advantage of the feature’s power savings options.

The study sampled observations from six of the most-downloaded apps on Google Play:

• Google Maps
• Google News
• Google Phone
• Google Calendar
• YouTube and
• Calculator

The researchers calculated the effect of “Dark mode: ON” on the Pixel 2, Moto Z3, Pixel 4 and Pixel 5 [All Google Android phones and apps] for 60 seconds.

OLED Draw Less Power in Dark Mode: On, But It’s Overall Impact on Energy Consumption Remains Unanswered

Since 2017, a majority of the smartphones that were launched in the market have an OLED screen, which draws much lesser power than older LCD screens. OLED screens allow the phone manufacturers to save cost spent on body and material, and compete within the market by delivering ultra-thin, super-flexible and even fold-able screen devices. But that doesn’t seem to have big impact on battery life.

At Purdue University,, Hu and his team have developed a power modeling technology to analyze and calculate the power drawn by OLED phone displays under working conditions. This tool is pending patent approval at the time of covering this development.

Here’s what they found:

1. At 30%-50% auto-brightness mode, Purdue researchers found dark mode: ON feature saves only 3%-9% power on an average. Higher brightness in switching to Dark Mode: ON delivers higher energy savings.
2. At 100% brightness levels, users could see savings between 39%-47% of battery power with Dark Mode: ON.
3. Taking an app scenario [Google News app], the researchers found Pixel 5 draws the same amount of energy at “50% brightness in Dark Mode: ON” as it would with 20% brightness in the conventional light mode.

Pranab Dash, a Purdue Ph.D. student who worked with Hu on the study, revealed: “Tests done in the past to compare the effects of light mode with dark mode on battery life have treated the phone as a black box, lumping in OLED display with the phone’s other gazillion components. Our tool can accurately isolate the portion of battery drain by the OLED display.”

What’s Next in the OLED Technology?

Coming soon: Apps designed with dark mode energy savings in mind

The team of Purdue University researchers have developed a tool for mobile app developers. The tool is called a Per-Frame OLED Power Profiler (PFOP). It is based on a patent-pending OLED power model that could make device brightness management work in sync with battery life.

The team also developed “Android Battery+” to track the battery life in Dark Mode savings at specific brightness levels.

So, dark mode saving battery life is actually a fact, and we are excited about the technology developments in the OLED industry as well as Purdue’s efforts to advance into Mobile Computing and Power/ Energy Management analytics.

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