⚡Convert amps to watts — and check the circuit

1,800 W at 120 V as a momentary maximum, and 1,440 W as a continuous load under the 80% rule. At 230 V a 15-amp circuit carries 3,450 W and 2,760 W continuously. Continuous means running three hours or more — a heater does, a toaster does not.

Voltage. Power is amps times volts, so at 230 V the same current delivers nearly twice the power. European kettles at 3,000 W boil in about half the time of a North American 1,500 W one, using almost the same total energy — just delivered faster.

Per hour yes, per job not necessarily. A 3,000 W kettle uses twice the power of a 1,500 W one but boils in half the time, so the energy used is close to identical. It is watts multiplied by hours that appears on the bill, never watts alone.

For resistive loads — heaters, kettles, incandescent bulbs — yes. For motors, transformers and some electronics, real power is amps × volts × power factor, where power factor is below 1. The simple multiplication slightly overestimates the power those devices actually consume, while correctly describing the current the wiring carries.

Current. A breaker measures amps, which is why the same 1,500 W appliance is fine on 230 V and marginal on 120 V. Breakers also tolerate brief surges — a motor starting draws several times its running current for a moment — which is why an appliance can start without tripping and still overload the circuit over time.

Two 1,500 W heaters on a single 15-amp 120 V circuit is 25 amps on a 15-amp breaker: it will trip, and if the breaker is faulty it will do worse. Check which outlets share a circuit before assuming two sockets on opposite walls are independent — in many homes a whole room is one circuit.