Courtesy of labnol.org

If you are curious to know the exact electricity cost of running your laptop or desktop computer all day long, here’s a quick guide.

Step 1: You first need to calculate the total power (in kilowatt) that’s consumed by your monitor, CPU, graphic card and other components of the computer.

Don’t worry – you don’t have to do these calculations manually. Joulemeter is a free software from Microsoft that can quickly estimate the power consumption of your computer based on the screen’s brightness, the microprocessor, etc.

Step 2: Now find the retail cost of electricity (commonly known as price per unit or price per kWh) in your part of the world. You can know the electricity cost per unit either from your last month’s electricity bill or check the official website of your power distribution company (search for electricity tariffs).

Once you have the two numbers, just multiply them to get an approximate idea of your computer’s electricity bill. I say approximate here because we are ignoring the power consumed by the modem, router and so on.
The Total Electricity Cost of Running a Computer.


Let’s take a practical example.

Assume that your computer monitor has a power rating of 50W. It will therefore consume 50×1/1000 or 0.05 kWh energy if you use the monitor for one hour. Now if the price of electricity in your region is 10¢ per unit, the total cost of running that monitor would be 8 x 10 x 0.05 or around 4¢ for an average eight-hour workday.

The monitor is just one component of the computer – you can use the above-mentioned Joulemeter software to calculate the total power consumed by all the various components of the computer and then multiply that number with the price of electricity to know the average running cost of the computer.

PS: The Joulementer application may upload certain anonymous information about your computer such as type of CPU and utilization; applications running; hard disk size and type; memory size and type; or the name of the Internet service provider and the IP address of your computer.