Electricity cost calculator

Energy in kWh = watts over 1000, times hours, times days; cost = kWh times the tariff. The month is your days-per-month figure and the year is that month times 12, so 30 days keeps the whole estimate one consistent approximation. Standby draw, tiered tariffs, time-of-use pricing, and fixed connection charges are not modeled. Tariff is a bare number; read it off your bill in your own currency per kWh. Repeat per appliance and add the results for a whole-home figure.