How to Calculate the Electricity Cost of Any Appliance (Watts to Dollars)
watts ÷ 1,000 × hours × your rate = dollars
Dividing by 1,000 turns watts into kilowatts. Multiplying by hours turns kilowatts into kilowatt-hours — kWh, the unit your bill charges for. Multiplying by your rate turns kWh into money. There is no fourth step.
A 2,000 W appliance run for one hour uses 2 kWh and costs 32.0¢ at the 2024 US average rate of $0.16/kWh. Run 8 hours a day it is $2.56 a day and $76.80 a month. And 54 kWh — the kind of number a meter reading shows — is $8.64 at that same rate.
The calculator below is already loaded with 2,000 W at 8 hours a day. Type the wattage off your own label over it, pick your state, and read the three cards.
Daily Cost
$2.56
16.0 kWh
Monthly Cost
$76.80
480.0 kWh
Yearly Cost
$934.40
5840.0 kWh
For perspective...
At $934.40/year, this is a major energy expense — equivalent to a car payment. Strongly consider more efficient alternatives.
Preloaded with 2,000 W at 8 hours a day and the US average rate. Picking a state swaps in that state's average; the rate box takes the exact figure off your bill if you have it. The same calculator, preloaded per appliance, sits on every appliance page on the site.
Two Worked Examples
A 2,000 W oven, one hour
2,000 ÷ 1,000 × 1 × $0.16 = $0.32
2,000 W is 2 kW. One hour of it is 2 kWh. At $0.16 a kWh that is 32.0¢ — less than a cup of coffee for a roast dinner. Ovens are expensive to buy and cheap to run.
A 105 W device, left on all day
105 ÷ 1,000 × 24 × $0.16 × 30 = $12.10/month
1.7¢ an hour sounds like nothing, which is exactly the trap. 2.52 kWh a day compounds to $147 a year — more than that oven costs across a whole year of hour-a-day roasts ($117), for a device nobody notices.
The two examples are the whole lesson: wattage sets the cost per hour, but hours set the bill. A big appliance used briefly is cheap; a small one that never switches off is not.
What One Hour Costs, by Wattage and Rate
Find your wattage down the left, your rate across the top. Every figure is watts ÷ 1,000 × 1 hour × the rate — the formula, run for you.
| Wattage | Energy per hour | 10.0¢/kWh | 15.0¢/kWh | 20.0¢/kWh |
|---|---|---|---|---|
| 100 W | 0.10 kWh | 1.0¢ | 1.5¢ | 2.0¢ |
| 500 W | 0.50 kWh | 5.0¢ | 7.5¢ | 10.0¢ |
| 1,000 W | 1.00 kWh | 10.0¢ | 15.0¢ | 20.0¢ |
| 1,500 W | 1.50 kWh | 15.0¢ | 22.5¢ | 30.0¢ |
| 2,000 W | 2.00 kWh | 20.0¢ | 30.0¢ | 40.0¢ |
The US average of $0.16/kWh sits just right of the middle column. The relationship is straight-line in both directions: double the wattage and you double the cost, double the rate and you double it again — so if your rate is 30.0¢, read the 15.0¢ column and double it. Your state's average is on the electricity rates page.
The Same Wattages Run 8 Hours a Day
Cents an hour is hard to feel. This is the same table at $0.16/kWh with the hours added — 8 hours a day, which is a heater through an evening and a night, an AC through a summer afternoon, or a desktop through a working day.
| Wattage | kWh/day | Cost/day | Cost/month30 days | Cost/yearif run all year |
|---|---|---|---|---|
| 100 W | 0.8 | $0.13 | $3.84 | $47 |
| 500 W | 4.0 | $0.64 | $19.20 | $234 |
| 1,000 W | 8.0 | $1.28 | $38.40 | $467 |
| 1,500 W | 12.0 | $1.92 | $57.60 | $701 |
| 2,000 W | 16.0 | $2.56 | $76.80 | $934 |
The yearly column is arithmetic, not a prediction — almost nothing runs 8 hours a day for all 365 of them. It is there to show the scale a habit reaches. A 1,500 W space heater is the row most people are actually looking for, and it only runs for the five months of a heating season.
Going the Other Way: kWh to Dollars
If you already have a kWh figure — off a meter, a bill, an EnergyGuide sticker, or a smart plug — there is no wattage step at all. Multiply by your rate and you are done.
| Energy | 10.0¢/kWh | 15.0¢/kWh | 16.0¢/kWhUS average | 20.0¢/kWh |
|---|---|---|---|---|
| 1 kWh | $0.10 | $0.15 | $0.16 | $0.20 |
| 10 kWh | $1.00 | $1.50 | $1.60 | $2.00 |
| 30 kWh | $3.00 | $4.50 | $4.80 | $6.00 |
| 54 kWh | $5.40 | $8.10 | $8.64 | $10.80 |
| 100 kWh | $10.00 | $15.00 | $16.00 | $20.00 |
| 500 kWh | $50.00 | $75.00 | $80.00 | $100.00 |
| 1,000 kWh | $100.00 | $150.00 | $160.00 | $200.00 |
54 kWh is $8.64 at the US average — about 3.4 days of a 2,000 W appliance run 8 hours a day, or 1.9 days of an average US household's whole electricity use. The table is linear, so a reading not listed is easy: 27 kWh is half the 54 kWh row, 250 kWh is half the 500.
Two Things That Make the Formula Overstate Your Bill
1. The nameplate wattage is a maximum, not an average
Anything with a thermostat draws its full wattage only while the element or compressor is energised, and coasts the rest of the time. A 2,000 W oven runs flat out through preheat and then cycles — at the 60% duty cycle the electric oven page models, an hour of baking is nearer 1.2 kWh than 2 kWh. A fridge is the extreme case: a nameplate of 150 W against the 550 kWh a year a standard top-freezer actually uses, which is 63 W held continuously — under half the label. Where an appliance publishes an annual kWh figure, use that instead of the nameplate: it already accounts for the cycling.
The exceptions, where watts × hours is exactly right: resistance heaters on a fixed setting, incandescent bulbs, kettles while boiling, and anything else with no thermostat and no variable output.
2. Your rate is probably not the one you think
The rate to use is your all-in rate: total dollars on the bill divided by total kWh billed. That folds in delivery, distribution, and fixed charges, and it usually lands a few cents above the supply rate a provider advertises. It is the only rate that makes a calculation match the bill it is trying to explain. Without a bill to hand, your state average is the next best thing — and state averages differ by a factor of 3.8, from 10.1¢ in Idaho to 38.8¢ in Hawaii, so it matters more than any other input on this page. The rates by state page lists all fifty and links each one straight into a calculator already priced at it.
Where to Find Your Appliance's Wattage
The nameplate
A sticker or moulded panel on the back or underside. If it lists volts and amps instead of watts, multiply them: 120 V × 12.5 A = 1,500 W.
The EnergyGuide sticker
Large appliances give estimated kWh per year rather than watts. Divide by 8,760 hours for the effective continuous wattage — the honest figure for anything that cycles.
A plug-in energy meter
Measures what the device actually draws, including standby. The only way to settle a wattage for something with several modes, and it accumulates kWh over days so you never have to guess the hours either.
Or skip the label entirely: the appliance comparison table publishes a typical wattage and typical daily hours for every appliance on the site.
Put It to Use
Appliance Cost Calculator
The formula on this page, run for 30+ appliances with wattages preloaded
Electricity Rates by State
The one input that changes every number above — find yours
Cost to Run an Electric Oven
A 2,000–2,500 W element, priced with the duty cycle the flat formula ignores
Cost to Run a Space Heater
1,500 W by the hour, month, and heating season — the one case where watts × hours is exact
The Cost of Running Appliances 24/7
What the 105 W example looks like across every always-on device in the house
How to Read Your Electricity Bill
Working out the all-in rate this page keeps asking you for
Frequently Asked Questions
How much does 2,000 watts cost per hour?
2,000 watts held for one hour is 2 kWh, so it costs whatever you pay for 2 kWh: 20.0¢ an hour at 10.0¢/kWh, 30.0¢ at 15.0¢, and 40.0¢ at 20.0¢. At the 2024 US average of $0.16/kWh it is 32.0¢ an hour. Run it 8 hours a day and that is $2.56 a day, $76.80 a month, and $934 a year.
How much is 54 kWh?
$8.64 at the US average rate of $0.16/kWh — $5.40 at 10.0¢/kWh and $10.80 at 20.0¢. kWh convert to dollars by multiplying, nothing more: 54 × your rate. For scale, 54 kWh is about 3.4 days of a 2,000 W appliance run 8 hours a day, or about 1.9 days of an average US household's total electricity use.
How do I convert watts to kWh?
Divide the watts by 1,000 to get kilowatts, then multiply by the number of hours it runs. A 1,500 W heater is 1.5 kW; run for 4 hours it uses 6 kWh. The division by 1,000 is the only step people skip, and skipping it overstates the bill by a factor of a thousand — a 1,500 W heater costs cents an hour, not dollars.
How much does 105 watts cost?
1.7¢ an hour at the US average rate — small enough that the hourly figure is not the useful one. Left on all day it is 2.52 kWh, about $12.10 a month and $147 a year. That is the range a games console left idle, an older fridge, or a desktop and monitor sit in, and it is why always-on devices matter more than their wattage suggests.
How much does a 2,000 W oven cost to run for an hour?
Less than the 32.0¢ the formula gives, because an oven element does not draw its full wattage for the whole hour. It runs flat out during preheat and then cycles on and off to hold temperature. At the 60% duty cycle this site's electric oven page models, an hour of baking is closer to 1.2 kWh — about 19.2¢. The same caveat applies to anything with a thermostat: fridges, freezers, water heaters, and space heaters all cycle.
What electricity rate should I use?
The all-in rate from your own bill, not the supply rate advertised by a provider. Divide the total dollar amount of the bill by the kWh it billed you for, and you get the number that includes delivery, distribution, and fixed charges spread across your usage — usually a few cents higher than the headline rate. If you do not have a bill to hand, your state's average is the best stand-in; the US average is $0.16/kWh, but state averages run from 10.1¢ in Idaho to 38.8¢ in Hawaii.
Where do I find an appliance's wattage?
Three places, in order of reliability. The nameplate — a sticker or moulded panel on the back or underside — lists watts, or lists volts and amps, which multiply to watts (120 V × 12.5 A = 1,500 W). The EnergyGuide sticker on large appliances gives estimated kWh per year instead; divide that by 8,760 hours to get the effective continuous wattage, which for a cycling appliance is the more honest figure. A plug-in energy meter measures what the device actually draws, which settles the question for anything that cycles or has multiple modes.
Does 2,000 watts mean it uses 2,000 watts the whole time it's on?
Only for appliances with no thermostat and no variable output — a resistance heater on its high setting, an incandescent bulb, a kettle while it boils. Anything that heats or cools to a setpoint draws its nameplate wattage only while the element or compressor is energised, and coasts the rest of the time. That is why a fridge with a 150 W nameplate does not cost 150 W × 24 hours a day: the 550 kWh a year a standard top-freezer uses works out to 63 W held continuously, under half the label. When a nameplate and a yearly kWh figure disagree, trust the kWh figure.