It is easy to calculate the energy cost of each appliance. Every electrical device or appliance is rated with power (watts), such as 40 W, 60 W, etc. This power is calculated based on the consumption of voltage and current of the device. Electricity consumption is a combination of the amount of electric power and the period of working time of the device.

The basic unit of electricity is the kilowatt hour (kWh). If a 1000-watt device is used for 1 hour, then it will consume the energy of 1 kWh (i.e., 1 unit).

21.1 : Steps for calculating the electricity bill

The following are the steps for calculating the electricity bill.

Step 1: Note down the wattage of each appliance.

Step 2: Multiply wattage with quantity to get total power in watts.

Step 3: Multiply total power with given working hours to get total energy in watt-hours.

Step 4: Divide watt-hours by 1000 to get kilowatt hours (kWh) or units.

Step-5: Multiply the number of units with the number of days in a given month to get the total number of units consumed in a month.

Step 6: Multiply total monthly unit cost per unit to get total monthly electricity bill.

Example:

One person is using two bulbs of 20W for 2 hours and one TV of 100W for 10 hours daily. calculate electricity bill for one month.

Bulb- 2hours *20w=40wh

Tv- 10 hours*100w = 1000wh

Total = 1040wh

Divide by 1000 to get in kWh

By dividing 1040wh with 1000 then 1.04kWh

Per day 1.4 units of power is consuming by the customer

Per month = 1.04 * 30 days =31.2 units

If assume per unit cost is 2.04 rupees then,

31.2 * 2.04 = 63.648 rupees have to pay.