How to calculate electricity cost
Here it is with your numbers:
- Multiply the watts by the hours a day and divide by 1,000: 1,500 × 1 ÷ 1,000 = 1.5 kWh a day.
- Multiply by the days it's used a year: 1.5 × 365 = 547.5 kWh a year.
- Multiply by the price, 18.16¢ ($0.1816) per kWh: 547.5 × $0.1816 = $99.426, rounded to $99.43 a year.
- Divide by 12 for a month: $99.426 ÷ 12 = $8.2855, rounded to $8.29.
It means running it this way costs $0.27 on each day it's used, $8.29 a month and $99.43 a year at 18.16¢ per kWh.
This is the Department of Energy's method. The calculator starts with its example kettle (1,500 W, about an hour a day), at the US average price. A month here is a twelfth of the year.
How to find an appliance's watts
- Look on the appliance. The watts are usually on the bottom, the back or the nameplate. That's the most it draws: on a lower setting it uses less.
- Multiply amps by volts. If the label shows amps instead, choose "Amps" above. Most US appliances use 120 volts; larger ones, such as clothes dryers and electric cooktops, use 240 volts.
- Use a plug-in electricity usage monitor. It shows the watts, and the kWh over time, for anything on a 120-volt outlet.
A refrigerator is plugged in all day but cycles on and off. The Department of Energy suggests dividing the time it's plugged in by three to estimate the hours it runs at full power: 8 hours a day.
What is a kilowatt-hour (kWh)?
Watts measure power at a moment; a watt-hour is one watt used for an hour. A kilowatt-hour (kWh) is 1,000 watt-hours, and it's what your electric bill charges for. A 40 W light bulb on for 5 hours uses 200 watt-hours, or 0.2 kWh.
Cost of a 1,000 W appliance
Used every day, at the US average of 18.16¢ per kWh.
| Hours a day | Per month | Per year |
|---|---|---|
| 1 | $5.52 | $66.28 |
| 2 | $11.05 | $132.57 |
| 4 | $22.09 | $265.14 |
| 8 | $44.19 | $530.27 |
| 12 | $66.28 | $795.41 |
| 24 | $132.57 | $1,590.82 |
What does electricity cost?
The average price for US homes was 18.16¢ per kWh in August 2026. It varies a lot by state, from 12.72¢ in Nevada to 47.18¢ in Hawaii. Your own price is on your bill. The Energy Information Administration updates these averages every month.
FAQs
How do I calculate electricity cost?
Multiply the watts by the hours a day and divide by 1,000 to get kWh a day. Multiply by the days you use it in a year, then by your price per kWh. The Department of Energy's example kettle uses 1,500 W for an hour a day: 1.5 kWh a day, 547.5 kWh a year, which at 11¢ per kWh is $60.23 a year.
How do I calculate the kWh of an appliance?
Multiply its watts by the hours you use it and divide by 1,000. A 1,500 W kettle used for 1 hour uses 1.5 kWh; a 360 W paper shredder used for 15 minutes uses 0.09 kWh.
How much does it cost to run a TV for 8 hours?
It depends on the TV's watts, shown on its label. A TV that uses 100 W, on for 8 hours, uses 0.8 kWh. At the US average of 18.16¢ per kWh, that's $0.15. Put your own TV's watts in the calculator with 8 hours a day.
Does leaving things plugged in but off still use electricity?
Yes. The Department of Energy says many appliances keep drawing a small amount of standby power when they are switched off, such as TVs, computers and kitchen appliances. You can stop it by unplugging them, or by switching off a power strip they are plugged into.
Is 20 kWh per day a lot?
It's less than average. In 2022 the average US home bought 10,791 kWh of electricity for the year, which is about 29.56 kWh a day. By state, it ranged from 6,178 kWh a year in Hawaii to 14,774 in Louisiana.
Source U.S. Energy Information Administration · How much electricity does an American home use? ↗
Sources
- U.S. Department of Energy: Energy Saver: Estimating appliance and home electronic energy use (archived copy, January 1, 2026)
- U.S. Energy Information Administration: Electric Power Monthly, Table 5.6.A: average price of electricity by state (August 2026)
- U.S. Energy Information Administration: How much electricity does an American home use?
- U.S. Energy Information Administration: Measuring electricity (watts, watthours and kilowatthours)