Calculator is an online tool to measure any one of the unknown quantity of Voltage, Power and Resistance by the two known quantities.
It is important to know the amperage of a circuit breaker so you don't overload the breaker with too many appliances. An overloaded circuit causes heat to build in the fuse box, which melts the wiring's plastic insulation. When insulation melts, current is no longer contained and an electrical fire may result. When in doubt about your electrical capacity, determine the amperage of your circuit breaker and don't overload the circuits.