PC Wattage is the amount of current consumed by a computer. A normal desktop computer uses 60 to 250 watts , while a laptop uses 15 to 45 watts. Different units in a PC uses different wattage. The cost of electricity is usually determined based on the kilo watt hour. Once you find watts used per hour you can multiply it by the number of watts used and divide it by thousand to find kilo watt hour.
This computer power supply calculator helps in determining the PC Watts Consumption.