Electricity Cost Calculator
Find what any appliance costs to run per day, month and year from its wattage, hours of use and your price per kWh — plus a table of common appliances at your rate.
Electricity Cost Calculator: with the default inputs, cost per month is $30.60.
From the label or manual. For kilowatts multiply by 1,000.
US residential average is about 17¢/kWh — check your bill for your rate.
- Cost per day
- $1.020
- Cost per year
- $367.20Daily cost × days per month × 12.
- Energy per month
- 180kilowatt-hours
- Energy per day
- 6kilowatt-hours
- Cost per hour of use
- $0.255
Assumptions
- The device draws its rated wattage the whole time it is in use.
- Yearly cost is the monthly figure × 12 using your days-per-month entry.
- Price is a flat rate per kWh; time-of-use and tiered tariffs are not modelled.
| Appliance | Watts | Hours/day | kWh/month | Cost/month |
|---|---|---|---|---|
| LED bulb (60 W equivalent) | 9 | 5 | 1.3 | $0.23 |
| Wi-Fi router | 10 | 24 | 7.2 | $1.22 |
| Laptop | 50 | 8 | 12 | $2.04 |
| 55-inch LED TV | 80 | 4 | 9.6 | $1.63 |
| Desktop PC + monitor | 200 | 8 | 48 | $8.16 |
| Refrigerator (compressor running) | 150 | 8 | 36 | $6.12 |
| Ceiling fan | 75 | 8 | 18 | $3.06 |
| Microwave | 1,000 | 0.25 | 7.5 | $1.28 |
| Dishwasher | 1,500 | 1 | 45 | $7.65 |
| Space heater | 1,500 | 4 | 180 | $30.60 |
| Hair dryer | 1,600 | 0.15 | 7.2 | $1.22 |
| Window air conditioner | 1,000 | 8 | 240 | $40.80 |
| Electric clothes dryer | 3,000 | 1 | 90 | $15.30 |
| Electric water heater | 4,000 | 3 | 360 | $61.20 |
| Central AC (3-ton) | 3,500 | 8 | 840 | $142.80 |
| Level 2 EV charger | 7,200 | 2 | 432 | $73.44 |
Wattages are typical figures from the US DOE appliance guide; check the label on yours. Fridges and AC units cycle on and off, so 'hours' is running time, not time plugged in.
How this is worked out
The formula
kWh per day = watts ÷ 1,000 × hours per day kWh per month = kWh per day × days per month cost = kWh × price per kWh
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Power draw
- From the label or manual. For kilowatts multiply by 1,000.0 or more · defaults to 1500
- Hours used per day
- A number.from 0 to 24 · defaults to 4
- Days used per month
- A number.from 0 to 31 · defaults to 30
- Electricity price
- US residential average is about 17¢/kWh — check your bill for your rate.in dollars · 0 or more · defaults to 0.17
- Number of units(under More options)
- Running three identical bulbs? Enter 3.from 1 to 1000 · whole numbers only · defaults to 1
What you get back
- Cost per monthmain answer
- Cost per day
- Cost per year
- Daily cost × days per month × 12.
- Energy per month
- kilowatt-hours
- Energy per day
- kilowatt-hours
- Cost per hour of use
What this assumes
- The device draws its rated wattage the whole time it is in use.
- Yearly cost is the monthly figure × 12 using your days-per-month entry.
- Price is a flat rate per kWh; time-of-use and tiered tariffs are not modelled.
About this calculator
Every electric bill is kilowatt-hours × price. A kilowatt-hour is 1,000 watts running for one hour — a 1,500 W space heater burns 1.5 kWh every hour it's on, which at 17¢/kWh is about 25¢ an hour, $1 for a four-hour evening, or $30 a month. This calculator does that arithmetic for any appliance and shows the result per day, month and year.
How to use it
- Power draw in watts — printed on the label, in the manual, or on the plug. If the label gives amps, multiply by the voltage (120 V in North America, 230 V in Europe). Devices that cycle (refrigerators, air conditioners, well pumps) list the running wattage; enter the hours they actually run, not the hours they're plugged in.
- Hours per day — be honest; a TV that's "on" six hours in the background counts.
- Price per kWh — the US residential average is around 17¢, but it ranges from about 11¢ in some southern and mountain states to 30–40¢ in California, Hawaii and New England. Your bill's total ÷ kWh used gives your true all-in rate, which includes delivery charges and is usually higher than the headline "supply" rate.
Reading the results
The headline is the monthly cost. The appliance table applies your rate to typical wattages so you can see at a glance where the money goes: heating and cooling dominate, followed by water heating, clothes drying and refrigeration. Electronics are nearly free by comparison — a Wi-Fi router left on all year costs about $15.
Ways to cut the bill
- Anything that makes heat (space heaters, dryers, ovens, hair dryers, kettles) is expensive per hour. Heat pumps move heat instead of making it and use a third of the energy.
- Standby ("vampire") power is typically 1–10 W per device — small individually, but 20 devices at 5 W is 876 kWh a year.
- Time-of-use tariffs can halve the cost of running a dryer or charging an EV overnight.
Accuracy
Label wattages are maxima; many devices draw less most of the time (a laptop charger rated 65 W averages 20–30 W). For a precise figure, a $15 plug-in energy meter records actual kWh over a week.
Frequently asked questions
▸How do I calculate how much an appliance costs to run?
Multiply its watts by the hours used, divide by 1,000 to get kilowatt-hours, and multiply by your price per kWh. A 1,500 W heater for 4 hours is 6 kWh, or about $1.02 at 17¢/kWh.
▸What is a kilowatt-hour?
The energy used by 1,000 watts running for one hour — the unit utilities bill in. Ten 100 W bulbs for one hour, or one 100 W bulb for ten hours, both use 1 kWh.
▸How much does it cost to run a space heater?
A 1,500 W heater on full costs 1.5 kWh × your rate per hour — about 25¢ at 17¢/kWh, or $30 a month for four hours a night. Thermostat cycling reduces this; heating a whole home this way does not.
▸Where do I find my electricity rate?
On your bill, divide the total amount by the kWh used for the true all-in rate including delivery. The US average is around 17¢/kWh but varies by more than 3× between states.
▸Do appliances use electricity when turned off?
Many do — standby power of 1–10 W for TVs, consoles, chargers and anything with a remote or a clock. A device drawing 5 W continuously uses 44 kWh a year, about $7.50.
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