2024 Electricity Cost Calculator
Estimate the cost of electricity and energy usage in kWh by entering its power consumption and the time the appliance or device is on per day. Learn about the power consumption of common appliances.
On this page:
- How to Estimate Electricity Cost and Energy Usage
- How to Calculate Your Electric Bill
- Step One: Calculate the Energy Used in Kilowatt-Hours
- Energy Used Per Day Formula
- Step Two: Calculate the Electricity Cost
- Electricity Cost Formula
- How to Calculate the Cost per Kilowatt-Hour
- Power Consumption of Common Appliances
How to Estimate Electricity Cost and Energy Usage
Homes these days are equipped with many electrical appliances, and we use dozens, if not hundreds, of other devices, making it difficult to predict overall energy usage.
The easiest way to estimate energy consumption in kilowatt-hours (kWh) and how much each appliance and device costs on your electric bill is to use the calculator above.
Continue reading to learn some easy formulas to calculate this yourself.
How to Calculate Your Electric Bill
To calculate how much an appliance contributes to your electric bill, first, calculate the energy used in kilowatt-hours (kWh), then calculate the total cost for the appliance.
Step One: Calculate the Energy Used in Kilowatt-Hours
The first step to estimating energy usage and costs is to calculate the kilowatt-hours (kWh) of energy used. Kilowatt-hours are a measurement of energy, where one kWh is equivalent to a power of one kilowatt consumed in one hour.
To calculate the kWh used per day, start by finding the power consumption of the appliance in watts. This could be marked on the device, in the owner’s manual, or in the technical specifications.
Next, multiply the power in watts by the hours used per day, then divide by 1,000 to get the kilowatt-hours used.
Energy Used Per Day Formula
The kilowatt-hour usage per day formula is:
E(kWh/day) = P(W) × T(hrs/day) ÷ 1,000 W/kWh
You can easily do this using a watts to kWh calculator.
Step Two: Calculate the Electricity Cost
To find the price for the kWh used, multiply by the rate per kWh charged by the electric company by the kilowatt-hours measurement found above.
Electricity costs vary by region, but the national average electricity rate is 13.87 cents per kilowatt-hour. This cost is shown on the monthly electric bill from the power company.
Electricity Cost Formula
The electricity price formula is:
Electricity Cost = Energy(kWh) × Rate(price/kWh)
Thus, the cost of electricity is equal to the energy used in kilowatt-hours multiplied by the electric rate.
For example, find the electricity cost per month to charge an electric vehicle for 4 hours per day using a 9,600-watt charger.
Find the kilowatt-hours:
E(kWh/day) = 9,600 W × 4 hrs/day ÷ 1,000 W/kWh
E(kWh/day) = 38.4 kWh/day
Calculate the cost:
Price per Day = Electricity(kWh) × Cost(cost/kWh)
Price per Day = 38.4 kWh/day × $0.1387
Price per Day = $5.33 per day
Price per Month = $5.33 per day × 30
Price per Month = $159.90
It would cost $159.90 per month to charge an electric vehicle for 4 hours per day using a 9,600-watt charger (assuming a 30-day month).
It’s also possible to use this formula to find out how much a light bulb or light fixture costs per month. Use our lighting cost estimator to find out how much lamps and light bulbs cost to keep on for the month and to find out how much money can be saved by upgrading to LED light bulbs.
How to Calculate the Cost per Kilowatt-Hour
Often the price per kilowatt-hour is included on your electric bill. But, you can calculate the price per kilowatt-hour using the following formula:
Price per kWh = Electric Bill Total – Electric Bill Taxes / Power Consumption in kWh
Thus, the price per kilowatt-hour is equal to the total electric bill minus taxes and fees, divided by the total power consumption in kilowatt-hours.
Power Consumption of Common Appliances
|Appliance / Device
|electric vehicle charger
|7,200W – 12,000W
|2,000W – 4,000W
|150W – 350W
|100W – 350W
|1,200W – 1,500W
|20W – 60W
|90W – 250W
|260W – 340W
|LED light bulb
|7W – 10W
|fluorescent light bulb
|16W – 20W
|60W incandescent light bulb
|25W – 75W
|10W – 25W
Our voltage drop calculator can calculate a drop in voltage, minimum wire size, and maximum wire length for your electrical project.
- U.S. Energy Information Administration, During 2021, U.S. retail electricity prices rose at fastest rate since 2008, March 1, 2022, https://www.eia.gov/todayinenergy/detail.php?id=51438
- U.S. Energy Information Administration, Table 5.6.A. Average Price of Electricity to Ultimate Customers by End-Use Sector, July 2022, https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a
- Miller, C., Ugly’s Electrical References, 2020 Edition, 2020, Jones & Bartlett Learning, 117. https://books.google.com/books?id=1kS8DwAAQBAJ
- NEC Co-op Energy, How to Calculate Your kWh Rate, August 10, 2020, https://neccoopenergy.com/how-to-calculate-your-kwh-rate/