We all use electricity in our home but do we really know how would they calculate the usage per month?.Electricity bill is calculated  based on how many units power we consumed per month.  Lets see how we do the simple unit calculation.Lets take the scenario ,we have 100 watts lamp which glow 5 hours per day.We are going to calculate how many units it consume per month and how much will it cost.

1 Unit = 1000 kilo watts

(Equipment Capacity) * (Usage) * (Number of days) / (UNIT)

Now apply our values into above formula.

(100) * (5) * (30)/1000 = 15

We consumed 15 units per month ,if each unit cost 10 rupees we need to pay 150 rs as bill.

Below are are example of sample capacity of the appliances we use in home

1.Electric Cooker = 1000 w
2.TV      = 120 w
3.Tube Light      = 125 w
4.Water Heater    = 2000 w
5.Iron Box      = 1000 w
6.Mixer                = 500 w
7.AC      = 1500 w
8.Washing Machine  =  325 w
9. Refrigerator     = 225 w
10.Fan   = 40 w

We need to add all the appliances we used in a home to calculate total power consumption and   EB charge per month.