Calculate the electric cost of an item, by adding item power consumption, usage time per day, and the tariff per KWh (means one Kilowatt-hour "KWh" cost).
Formulas:
Converting watts and kilowatts
Kilowatts to Watts formula:
Watts (W) = KW x 1000
1 KW = 1 x 1000 = 1000 Watts (W)
Watts to Kilowatts formula:
Kilowatts (KW) = W ÷ 1000
100 W = 100 ÷ 1000 = 0.1 Kilowatts (KW)
KWh consumption formula:
KWh consumption (energy) = Power x Time
Example:
Power = 2 KW
Time = 3 hours
kWh = 2 x 3 = 6 KWh
KWh Cost formula:
Cost = KWh used x Tariff per KWh
Example:
Power = 2 KW
Time = 3 hours
So the kWh = 2 x 3 = 6 KWh
Tariff = $0.10 per KWh
Cost = 6 KWh x $0.10/KWh = $0.60