Head to the Google Play Store and download Battery Percent Enabler. Run the app, read its short explanation if you like, and then simply check the box and reboot your device. Now you’ll have your phone’s exact battery percentage displayed inside the battery icon!
On KitKat, you’ll notice that you can’t see the battery percentage unless it’s below 40% or so because of a head-scratcher of a UX decision; someone made the text color identical to the battery fill color. The app’s developer can’t fix this because it’s hard-coded into a system file, which would require root access. On Lollipop (5.x)Android 5.0 Lollipop: What It Is And When You'll Get ItAndroid 5.0 Lollipop: What It Is And When You'll Get ItAndroid 5.0 Lollipop is here, but only on Nexus devices. What exactly is new about this operating system, and when can you expect it to arrive on your device?Read More, they adjusted this and you can see the battery percentage starting at 99%.
Once you’ve rebooted, feel free to remove the app from your phone. You don’t need it unless you want to remove the percentage, in which case you’ll need to reinstall, uncheck the box, and then reboot again.
ANDROID M HAS EMBEDDED BATTERY PERCENTAGE IN THE STATUS BAR