Calculate electrical power, voltage, current, and resistance from any two known values.
A watt (W) is the unit of electrical power. It represents one joule of energy per second. Common appliances range from 10W (LED bulb) to 5000W (oven).
Multiply power (kW) by hours of use, then by your electricity rate. Example: 2kW heater × 8h = 16 kWh × $0.12 = $1.92/day.
Watts = Volts × Amps. To increase power, you can increase either voltage or current.