A free app for Android, by Widget7.
Wifi Calling is a revolutionary new service that allows you to make phone calls over Wi-Fi. In just a few seconds, you can start using it without any setup costs or hassle. All you need is a Wi-Fi connection.
It works on any phone that supports Wi-Fi calling, and the service is available on all four major US carriers as well as on many other carriers worldwide.
Wifi Calling is an extremely useful service that you can use when you’re in an area with weak carrier coverage. It can also be useful when you’re trying to place a call in a dingy, underground bar (assuming you can connect to the bar’s Wi-Fi, that is).