Prepaid Electricity Tracker

I am an individual and require an app to be build to calculate electricity consumption and keep a track of electricity costs and consumption based on readings input. There should be a settings page where the user can input currency and rate of electricity as well as unit of measure of electricity. On the main page the user must be able to either input a reading and the reading should be captured in a database with a time date stamp. The user could also input recharge amount and the program should take the last reading and add the recharge total to it. Recharges should also be tracked in the database with a date time stamp. On another page the user must be able to track usage based on readings and recharges and see consumption graphs etc. For daily , weekly or monthly. All of this data should be hosted in a cloud and different family members should be able to link their apps to the same data to keep track or to input data.