Keeptab DarkDoes dark mode save battery? Yes, but less than you think
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In short: Dark mode does save battery, but only on OLED screens and mostly when brightness is high. A Purdue study found savings of 39% to 47% at full brightness, and only 3% to 9% at the 30% to 50% brightness most people use indoors.[1] Google says the gain depends on the screen technology.[2]
Does dark mode save battery? The honest answer is “it depends”, which is annoying, so here is exactly what it depends on. Two things matter: the kind of screen you have, and how bright you keep it.
The short answer from Google
Android's developer guide lists battery first among the benefits of a dark theme: it “reduces power usage by a significant amount, depending on the device's screen technology”.[2] Google Drive's help says the same thing more modestly: its Dark Mode setting can help save battery life.[3]
Notice the condition in Google's sentence. The screen technology decides almost everything.
Why the type of screen matters
On an OLED screen, each pixel makes its own light. There is no backlight, as there is on LCD screens, so a dark pixel draws less power than a bright one.[1] Purdue University notes that smartphones released after 2017 likely have an OLED screen.[1]
That's the whole trick. Dark mode saves power because it turns most of the screen dark. The saving comes from the pixels, so it only exists where the pixels make their own light.
How much battery does dark mode really save?
In 2021, Purdue researchers measured it on four Android phones (Pixel 2, Moto Z3, Pixel 4 and Pixel 5) with six popular apps, including Google Maps, YouTube and Calendar.[1] Their tool isolated the power used by the display itself, which earlier tests had lumped in with the rest of the phone.[1]
Here's the catch. Auto-brightness tends to keep phones around 30% to 40% most of the time indoors.[1] At that level, the researchers say the saving is so small that most people wouldn't notice the longer battery life.[1] Outside on a sunny day, when your screen climbs to full brightness, dark mode makes a real difference.
One more finding is a nice bonus. On a Pixel 5, the Google News app at 20% brightness in light mode drew the same power as at 50% brightness in dark mode.[1] So if dark text is easier for you to read with the brightness turned up, you're not paying extra for it.
When dark mode is worth turning on for battery
- Outdoors and in bright places. That's when your screen is brightest, so that's when dark mode saves the most.[1]
- When your battery is low. On Pixel phones, turning on Battery Saver also turns on the dark theme.[2]
- Lower the brightness first. Brightness weighs more than the theme: a dimmer screen in light mode can draw as much as a brighter one in dark mode.[1]
- Don't trust the battery screen for this. Purdue found that Android's battery usage feature doesn't take what's on screen into account, so it won't show the effect of dark mode.[1]
Docs, Sheets and Slides in real dark mode. Keeptab Dark turns the whole Google Docs, Sheets, Slides and Excel page dark. Images keep their colors, and there is no white flash. Alt+Shift+D turns it on or off.
Add to Chrome — it's freeOn a computer, it's about your eyes
Most of the battery debate is about phones. On a computer, the better reason to go dark is comfort: eye doctors say dark mode cuts the glare of a bright screen in a dark room. We cover that in is dark mode better for your eyes.
The problem is that your documents rarely follow. In a browser, Google Docs, Sheets and Slides stay white, as does Excel for the web. We make Keeptab Dark, a Chrome extension that turns those pages dark on your screen without changing the file for anyone else.[4] We won't promise you hours of battery with it. We'll promise you a page that stops glowing at 11 p.m. If Docs is your main tool, start with our guide to dark mode in Google Docs.
FAQ
Does dark mode really save battery?
Yes on OLED screens. A 2021 Purdue study measured average savings of 39% to 47% at full brightness, but only 3% to 9% at 30% to 50% brightness, the range most people use indoors.
Does dark mode save battery on an LCD screen?
The saving comes from OLED pixels making their own light, which lets dark pixels draw less power. LCD screens use a backlight instead, so the Purdue explanation doesn't apply to them.
Does dark mode or lower brightness save more battery?
Brightness matters a lot. Purdue found that light mode at 20% brightness can draw the same power as dark mode at 50% on a Pixel 5.
Sources
- Purdue University, Elmore Family School of Electrical and Computer Engineering. Dark mode may not save your phone's battery life as much as you think (2021). https://engineering.purdue.edu/ECE/News/2021/dark-mode-may-not-save-your-phones-battery-life-as-much-as-you-think-but-there-are-a-few-silver-linings
- Android Developers. Implement dark theme. https://developer.android.com/develop/ui/views/theming/darktheme
- Google Drive Help. Use Dark Mode in Google Drive. https://support.google.com/drive/answer/9962935?hl=en&co=GENIE.Platform%3DAndroid
- Keeptab Dark. Dark mode for Google Docs, Sheets, Slides and Excel. https://keep-tab.com/dark/
Docs, Sheets and Slides in real dark mode
Keeptab Dark turns the whole Google Docs, Sheets, Slides and Excel page dark. Images keep their colors, and there is no white flash. Alt+Shift+D turns it on or off.
Add to Chrome — it's free