Voltage Widget is a free Android app developed by Glee Fabric in the Utilities & Tools category. This app displays your device's battery voltage as a value in mV, with customizable text size and color. It is particularly useful for users who want to have a reference on their device's available charge level, especially when state of charge estimation algorithms have problems with current battery level estimation due to battery aging or environmental temperature changes.

One of the peculiarities of Voltage Widget is that the last configuration of text size and color will be applied to all widget instances. However, it should be noted that on some devices, the Android system provides voltage in volts instead of millivolts, so this app may be useless in determining this parameter. Overall, Voltage Widget is a simple and straightforward app that does what it promises, making it a useful addition for users who want to monitor their device's battery voltage.