A Free Calculator · Your Rate, Your Appliance · Updated 2026
What does it cost to run that appliance?
Running cost is just wattage, time, and your electricity rate. Enter how much power an
appliance draws, how many hours a day you use it, and what you pay per kilowatt-hour, and
this calculator returns the cost per day, per month, per year, and per hour. Every formula
is shown, nothing is hidden, and the built-in wattages are starting points you can override.
Cost per day, month & year·Energy used per year·Your own electricity rate
Read this first
This calculator does the arithmetic exactly — but it's only as accurate as your inputs.
The built-in appliance wattages are approximate typical figures and vary widely by
model, size, and efficiency; whenever you can, override them with the number on your
appliance's nameplate or label. And remember that refrigerators and freezers cycle on and
off — enter the effective hours they actually run (roughly 8 per day), not the 24 hours
they're plugged in.
Cost to run an appliance — per day, month, and year
Pick an appliance (or type your own wattage), set how often you use it, enter your electricity rate, and the results update as you go. Use the appliance's nameplate wattage and your real hours for the most accurate number.
Your appliance & usage
Typical wattages — vary by model; use the nameplate/label on your appliance. Picking one fills the box; you can still edit it.
W
Find this on the appliance label or nameplate (watts, or volts × amps).
hrs/day
Refrigerators/freezers cycle on and off — enter the effective hours they actually run (~8/day), not 24.
days/yr
Lower this for seasonal use (e.g. a window AC run ~120 days).
$/ kWh
From your electric bill. The U.S. residential average is roughly 16–17¢/kWh but varies widely by state — check current EIA data.
Running this costs
Cost per day
Cost per month
Energy per year
Cost per hour
The formulas, in full
Nothing here is a black box. These are the exact calculations the tool runs — the same
arithmetic you could do on paper. The only judgment calls are the inputs you supply.
How each number is derived
1 — Energy used per day
daily_kWh = (watts ÷ 1000) × hours_per_day
2 — Cost per day
daily_cost ($) = daily_kWh × rate
3 — Energy used per year
annual_kWh = daily_kWh × days_per_year
4 — Cost per year
annual_cost ($) = annual_kWh × rate
5 — Cost per month
monthly_cost ($) = annual_cost ÷ 12
6 — Cost per hour of running
cost_per_hour ($) = (watts ÷ 1000) × rate
Typical appliance wattages
A starting-point reference for common household appliances. The cost columns show what each
would cost per year at one hour and three hours of use per day, assuming a $0.17/kWh rate.
Every figure is approximate and illustrative — your appliance's nameplate wattage and your
own rate are the numbers that matter, so enter them in the calculator above.
Appliance
Typical watts
At 1 hr/day
At 3 hrs/day
Space heater
~1500 W
$93.08/yr
$279.23/yr
Window AC (10k BTU)
~1000 W
$62.05/yr
$186.15/yr
Refrigerator
~150 W
$9.31/yr
$27.92/yr
Clothes dryer (electric)
~3000 W
$186.15/yr
$558.45/yr
Dishwasher
~1800 W
$111.69/yr
$335.07/yr
Electric water heater
~4000 W
$248.20/yr
$744.60/yr
Microwave
~1000 W
$62.05/yr
$186.15/yr
Desktop computer
~200 W
$12.41/yr
$37.23/yr
LED TV 55-inch
~80 W
$4.96/yr
$14.89/yr
LED bulb
~10 W
$0.62/yr
$1.86/yr
Cost columns assume a $0.17/kWh electricity rate and the typical wattage shown, run that
many hours every day of the year (cost/yr = watts ÷ 1000 × hrs/day × 365 × 0.17). They are
illustrative only — wattages vary by model and your rate is likely different. Note that a
fridge cycles on and off rather than running a fixed number of hours, so its real annual
cost is closer to the figure you'd get by entering ~8 effective hours per day in the
calculator above.
Getting a number you can trust
The arithmetic is exact, so accuracy comes down to three things: the appliance's real
wattage, the hours it actually runs, and the rate you actually pay. Here's where each one
comes from and why the big loads deserve the most attention.
Where to find your appliance's real wattage
Check the nameplate or rating label, usually on the back, base, or inside the door of the appliance. It shows watts (W) directly, or volts and amps — multiply them (watts = volts × amps) to get the draw. A label reading 120 V and 10 A means about 1,200 W. Treat any "max" rating as an upper bound rather than the typical running draw. The most reliable method is a plug-in energy meter, which reads the real draw and totals energy over time.
Big always-on loads dwarf the small stuff
Heating and cooling loads run the cost: an electric water heater (~4,000 W), central AC (~3,500 W), and electric dryers and ovens (~2,400–3,000 W) cost far more per hour than electronics. And an always-on appliance like a refrigerator, running every day of the year, can quietly out-cost a high-wattage device you use occasionally — annual cost is wattage times hours times days, and the days add up. Run your biggest suspects through the calculator first; the small devices rarely move the needle.
Standby power adds up
Many devices keep drawing a few watts when "off" — chargers, TVs, game consoles, anything with a clock, remote, or standby light. Individually it's pennies, but across a houseful of electronics it becomes a real always-on load. To estimate just the idle draw of a single device or your whole home's standby total, use the phantom load calculator instead, which is built for those small continuous watts.
How to get the most accurate estimate
Four inputs drive the result. Tightening up the wattage and the hours — the two that vary
most in the real world — does the most to make the number trustworthy.
Read the nameplate label
Find the rating label on the appliance and use the watts it lists, or multiply the volts by the amps. This beats the dropdown's typical value, which is only an approximate starting point for that category of appliance.
Time how you really use it
Be honest about hours per day and days per year. A space heater might run 4 hours a night for only the 100 coldest days; a window AC might run 8 hours a day for 120 summer days. For a fridge or freezer, enter the effective hours the compressor runs (~8/day), not the 24 hours it's plugged in.
Use your actual electricity rate
Pull your latest electric bill and total the supply + delivery charges, then divide by the kWh used to get your true blended rate. If you're on a time-of-use plan, use the rate for the hours you actually run the appliance — overnight off-peak rates can be far cheaper.
Measure it with a plug-in meter
For anything that cycles or varies — fridges, well pumps, dehumidifiers — a plug-in energy monitor logs real energy use over days and removes the guesswork. Read the accumulated kWh, divide by the number of days, and you have a measured daily figure that beats any nameplate estimate.
Where to buy
Got your numbers? Here's where to pick up what you need:
The units and terms that show up on an appliance label, a spec sheet, or an electric bill —
in plain English.
Watt (W)
A unit of power — the rate at which an appliance draws energy at any instant. A 60 W bulb draws 60 watts the whole time it's on. It is the number on most appliance labels, or you compute it as volts × amps.
Kilowatt-hour (kWh)
A unit of energy — the total amount used over time, and the unit your utility bills you in. One kilowatt of power drawn for one hour equals one kWh. A 1,000 W appliance run for 3 hours uses 3 kWh.
Kilowatt (kW)
One thousand watts. Dividing an appliance's watts by 1,000 converts to kilowatts, which is the step this calculator takes before multiplying by hours to get kWh. A 1,500 W heater is 1.5 kW.
Duty cycle
The fraction of time an appliance's main load actually runs while it's switched on. A refrigerator is plugged in 24 hours a day but its compressor may run only about a third of that, so its effective hours are far lower than its plugged-in hours — which is why you enter effective running hours, not 24.
Electricity rate ($/kWh)
The price your utility charges per kWh, found on your bill (sometimes split into supply and delivery charges — add them for an all-in rate). It varies by state, utility, season, and sometimes time of day, which is why this tool asks you to enter your own rather than baking in an average.
Standby / phantom load
The small continuous power a device draws when "off" but still plugged in — to keep a clock, remote sensor, or standby light alive. A few watts per device, but it runs every hour of the year. For that specific case, the phantom load calculator is the better tool.
Frequently asked
Look for a nameplate or rating label, usually on the back, bottom, or inside the door of the appliance. It lists the power draw in watts (W) directly, or it lists volts (V) and amps (A) — multiply them to get watts, since watts = volts × amps. A device labeled 120 V and 5 A draws about 600 W. If the label only shows a maximum or peak figure, that is the worst case, not the typical running draw, so treat it as an upper bound. The most reliable method is to measure the appliance with a plug-in energy meter, which reads the real-time and accumulated draw. The wattages built into the dropdown on this page are approximate typical figures and vary by model — always override them with your appliance's actual label or a measured value when you can.
Refrigerators and freezers do not run continuously — their compressors cycle on and off to hold a set temperature. A fridge plugged in 24 hours a day might have its compressor actually running only 8 to 10 hours' worth in that period. This is called the duty cycle. So even though the nameplate or your meter shows a draw of around 150 W while the compressor is on, the effective running time is far less than 24 hours. That is why the hours-per-day field on this calculator asks for the effective hours the appliance actually runs, not the hours it is plugged in. For a fridge, entering roughly 8 hours per day gives a far more realistic cost than entering 24. A plug-in meter that logs energy over a few days is the most accurate way to capture the cycling.
The biggest electricity users are almost always the loads tied to heating and cooling: electric resistance space and water heating, central air conditioning, and electric clothes dryers and ovens. An electric water heater (around 4,000 W) or central AC (around 3,500 W) running for hours dwarfs the cost of small electronics, even though there are far more small devices in the house. Always-on loads matter too — a refrigerator that runs every day, every hour of the year, can quietly out-cost a high-wattage appliance you only use occasionally. The way to find your own answer is to run each appliance through this calculator with its wattage and your real hours and days of use; the annual figures make the big loads obvious. Phantom standby draw from idle electronics is usually a small slice, but it adds up across dozens of devices.
Cost is wattage × hours × days × rate, so you can pull any of those four levers. Cut hours by running the appliance less or using timers and smart plugs. Cut wattage by replacing an energy hog with an efficient model — an ENERGY STAR appliance or LED lighting can use a fraction of the power for the same result. Cut your rate by shifting use to off-peak hours if your utility offers time-of-use pricing, or by checking whether a different supplier is cheaper. For the big always-on loads — water heater, fridge, HVAC — even small efficiency gains compound over thousands of hours a year. For small electronics, eliminating standby draw with a switched power strip is the easy win. Run your before-and-after numbers through this calculator to see the dollar difference rather than guessing.
Watts (W) measure power — the rate at which an appliance draws energy at any instant. Kilowatt-hours (kWh) measure energy — the total amount used over time, which is what your utility bills you for. They are linked by time: power multiplied by hours equals energy. A 1,000 W (1 kW) appliance running for one hour uses 1 kWh. Run that same 1,000 W appliance for three hours and it uses 3 kWh. To get from watts to the kWh on your bill, divide watts by 1,000 to get kilowatts, then multiply by the hours of use. This calculator does exactly that: it converts your appliance's wattage and hours into kWh, then multiplies by your rate per kWh to get a dollar cost.
For most appliances the per-hour cost does not change with the season — a microwave costs the same to run in January as in July. What changes is how much you use heating and cooling loads, and sometimes your electricity rate. In winter, electric space heaters and electric water heaters work harder and run more hours, so their annual cost climbs even though the wattage is unchanged. In summer, air conditioners and dehumidifiers dominate. Some utilities also charge higher rates during peak demand seasons or peak hours. To capture seasonal use, lower the days-per-year field for an appliance you only run part of the year — for example, set a window AC to around 120 days rather than 365 — and enter the rate you actually pay during that season.
Common mistakes with this calculator
These are the four input errors that produce the most inflated or misleading results.
Using the nameplate peak watts instead of the running draw
Appliance labels often show the maximum rated wattage — the worst-case draw at full load, not the steady running draw. A refrigerator compressor may surge briefly to 600 W but sustains roughly 150 W while cycling. Entering the peak figure inflates your annual cost estimate significantly. Use the running wattage, not the maximum.
Entering 24 hours per day for a refrigerator or freezer
Refrigerators cycle their compressors on and off — the fridge is plugged in 24 hours a day, but the compressor typically runs for only about 8 of those hours. Entering 24 hours overstates annual cost by roughly 3×. Use effective running hours (about 8/day for a typical fridge), or measure with a plug-in energy monitor over several days. Source: US DOE appliance test procedures use a 24-hr compressor-run-time figure, not 24 hrs at full wattage.
Using the national average rate instead of your real blended rate
U.S. electricity rates range from under 10¢/kWh in some states to over 30¢/kWh in others. Using a national average when your actual rate differs can change the result by 2× or more. Pull your real blended rate from your electric bill (total charges ÷ kWh used). If you're on a time-of-use plan, enter the rate that applies during the hours the appliance actually runs.
Leaving days-per-year at 365 for seasonal appliances
A window AC, space heater, or pool pump typically runs only part of the year. Leaving days at 365 for a unit you actually run for 120 summer days overstates annual cost by 3×. Set the days field to how many days per year the appliance actually operates.