An electricity bill is calculated based on how much electricity you use.
The amount of electricity you use is measured in KWH and for every KWH you use you're charged between 10 cents to 30 cents per KWH depending on your cost of electricity.
The kilowatt-hour is a unit of energy equal to one kilowatt of power sustained for one hour or to 3600 kilojoules. It is commonly used as a billing unit for energy delivered to consumers by electric utilities.
1 KWH is equal to 1000 watts so for every 1000 watts you use of electricity you're charged the 10 cents to 30 cents per 1000 watts depending on your electricity costs.
To calculate the electricity cost($) of operating an appliance, you would need to multiply the electricity consumption(kWh) by the tariff rate (say 20 cents/kWh).
To get the energy consumption (kWh), multiply the appliance wattage (kW or W) by the number of hours you use.
There's also the fixed charges that are added to the electric bill as well regardless of how much electricity you use.
The fixed charges of an electricity bill are monthly charges that the electricity company charges that help to cover costs such as to maintain your service, maintain the electric grid, etc.
These fixed charges do not change from month to month but may change and go up years later as the cost of things go up.
For example a fixed charge can be a monthly membership fee that you pay to the electricity company whether you use electricity or not.
That amount is paid whether you use any electricity or not.
An example would be I pay my electricity company $28.00 per month to keep my electric service established whether I turn anything on or not.
The KWH charges are what is charged for each KWH you use so the more electricity you use the more your electric bill will cost.
The less electricity you use the less your electricity bill will be.
The Fixed Charge of an electric bill is applied to recover the basic cost of electric service, independent of how much energy is used.
It is rent for using Electric's investment in equipment like poles, wires, and transformers, as well as labor to provide members with safe and reliable electric service and also do repairs of the wires, poles etc in the event of a storm or something that knocks power out.