Cost of Energy Calculator
Your electricity bill states a total, but not what any single choice costs: the heater in the spare room, the second fridge, the month the air conditioning never cycled off. This calculator prices energy directly, from the two numbers everything else is built on: how many kilowatt-hours you used and what you pay for each one.
Enter consumption and rate to get the energy cost, what that usage runs per day, and the annual figure if the same usage held all year.
How it was calculated
Energy charges only. Fixed service fees, and commercial demand charges based on peak kilowatts, are not part of the kWh times rate formula.
Quick Answer
Key takeaways
- Energy cost = kWh x rate. Every electricity estimate, from one bulb to a factory, is some version of that multiplication.
- Your all-in rate is total bill divided by kWh. It runs higher than the advertised supply rate because delivery, riders, and taxes ride on top.
- To price one appliance, convert first: watts divided by 1,000, times hours run, gives its kWh.
- Electricity is also one line in the household budget; see how it sits inside the full monthly picture in the cost of living section below.
How to use the cost of energy calculator
Take the consumption figure from your latest bill or meter read; it is printed as kWh used for the period. Take the rate from the same bill by dividing the total due by that kWh figure, which gives your all-in rate including delivery and taxes. Enter both, press Calculate, and you get the period cost, a per-day figure, and the annualized cost and consumption if nothing changed.
For a single appliance, work out its kWh first: watts divided by 1,000, multiplied by the hours it runs in the period. If you are converting between watts, amps, and volts to get that wattage, the amp watt calculator handles the electrical side. Heat loads measured in British thermal units convert through the cost per BTU calculator in this batch, which prices energy by the BTU instead of the kWh.
The formula, and the rate mistake that skews most estimates
One multiplication prices all of it, and the US Department of Energy teaches the same formula for appliance costs.
The common error is the rate, not the arithmetic. Bills advertise a supply rate, but delivery charges, transmission riders, and taxes can add a third or more on top. The EIA Electric Power Monthly reports average revenue per kWh by state and sector precisely because the all-in figure is what households actually pay. Price your usage with the supply rate alone and you will understate every appliance decision that follows, from whether a space heater is cheap to run to whether a solar quote pencils out. Divide last month's total due by last month's kWh once, write that number down, and use it everywhere.
Worked example: pricing a home month and a space heater
The calculator is pre-filled with a typical home month: 900 kWh at $0.17 per kWh.
| Case | Consumption | Rate | Cost |
|---|---|---|---|
| Whole home, one month | 900 kWh | $0.17 | $153.00 |
| Space heater, 1,500 W, 8 hrs a day, 30 days | 360 kWh | $0.17 | $61.20 |
| LED bulb, 10 W, 5 hrs a day, 30 days | 1.5 kWh | $0.17 | $0.26 |
| EV charging, 300 kWh a month | 300 kWh | $0.17 | $51.00 |
The heater row is why this simple tool earns its place. A heater that feels free because it plugs into a wall socket adds $61.20 a month at an ordinary rate, about 40% of a typical home's entire electricity spend, while the LED bulb is a rounding error at 26 cents. Ranking your loads by cost, not by how big they look, is the whole game, and it takes one multiplication per load. Electricity then rolls up into the household total alongside housing, food, and transport in the cost of living calculator.
What competing calculators miss
Most electricity cost tools reviewed for this page start from watts, hours per day, and days per month for one appliance at a time. That is useful, but it misses how people actually check a bill.
Miss 1: no direct kWh entry. Your bill already states total kWh. Forcing you to rebuild that figure appliance by appliance, with duty-cycle guesses for the fridge and the water heater, adds error to a number you already know exactly. Here the bill figure goes straight in.
Miss 2: advertised rates instead of all-in rates. Tools that pre-load a state average supply rate understate your cost, because delivery and taxes never appear. This page teaches the total-due divided by kWh method and lets your real rate drive the result.
Miss 3: a single period, no context. A bare monthly total does not tell you whether usage is light, typical, or heavy. The verdict here bands your kWh against the EIA typical home range, and the annual view turns a forgettable monthly figure into the $1,836 a year that actually motivates a fix.
One honest limit: tiered and time-of-use tariffs price different kWh at different rates. If your utility charges more after a threshold or during peak hours, split the usage into blocks and run each block at its own rate, then add the results.
Frequently Asked Questions
Multiply the energy used, in kilowatt-hours, by your price per kilowatt-hour. 900 kWh at $0.17 per kWh costs $153.00. Your bill or meter gives you the kWh figure; your tariff or the total-due line divided by kWh gives you the rate.
A kilowatt-hour is 1,000 watts running for one hour. A 100-watt bulb left on for 10 hours uses 1 kWh, and so does a 2,000-watt heater running for 30 minutes. Utilities meter energy in kWh because it captures both how hard a device draws and for how long.
The US Energy Information Administration puts the national residential average in the high teens of cents per kWh in its recent Electric Power Monthly releases, with state averages running from roughly 12 cents to over 40 cents in Hawaii. Your own all-in rate, total bill divided by kWh used, is the only figure that prices your usage correctly.
Divide the total amount due by the total kWh for the same period. That all-in rate includes delivery, riders, and taxes spread over your usage, which is the right rate for comparing appliances. If your bill lists a separate supply rate, use that only when you want the energy-only cost.
The EIA Residential Energy Consumption Survey and utility data put a typical US home near 850 to 900 kWh a month, with wide swings by climate, home size, and whether heating, cooling, and hot water are electric. At $0.17 per kWh, 900 kWh costs $153.00 for the month.
Yes. Find the appliance usage in kWh first: watts divided by 1,000, times hours run. A 1,500-watt heater running 8 hours a day for 30 days uses 360 kWh, which at $0.17 costs $61.20 for the month. Enter 360 as the consumption and your rate as the price.
No. It prices energy only: kWh times rate. Fixed monthly service charges do not change with usage, and commercial demand charges price your peak kilowatts, not your total kWh, so both sit outside this formula. Add them from your bill if you need a full invoice estimate.
Add This Calculator to Your Website
References
- US Energy Information Administration, "Electric Power Monthly": average revenue per kilowatt-hour by state and sector, the source for all-in residential rate comparisons. EIA: Electric Power Monthly. Accessed October 2026.
- US Energy Information Administration, "Residential Energy Consumption Survey (RECS)": how much energy US homes use, by end use, region, and housing type. EIA: Residential Energy Consumption Survey. Accessed October 2026.
- US Department of Energy, Energy Saver, "Estimating Appliance and Home Electronic Energy Use": the watts to kWh to cost method used for the appliance examples on this page. DOE Energy Saver: Estimating Appliance Energy Use. Accessed October 2026.
- ENERGY STAR, "Appliances": certified appliance energy data and operating-cost comparisons for refrigerators, laundry, and dishwashers. ENERGY STAR: Appliances. Accessed October 2026.
- US Energy Information Administration, "Electric Sales, Revenue, and Average Price": annual utility data behind average bill and average price statistics. EIA: Electric Sales, Revenue, and Average Price. Accessed October 2026.