Electricity Cost Calculator: What an Appliance Costs to Run
Multiply the appliance's kilowatts by the hours used and by your electricity rate to get the cost. A 1,500 W heater run 2 hours a day at $0.16 per kWh costs about $0.48 a day, or roughly $14.40 a month.
Estimated cost
$0.480
per day
Per day
$0.480
Per month
$14.40
Per year
$175.20
3 kWh used per day, at $0.1600 per kWh.
Assumes the same usage every day of the month and year — for something used only a few days a week, multiply the daily cost by how many days it's actually on instead of using the monthly/yearly figures directly. Check a recent bill for your exact rate; it varies by location, provider and time of use.
Show the math
- 1
Convert watts to kilowatts
1,500 W ÷ 1000 = 1.5 kW
Electricity is billed per kilowatt-hour, so watts are converted to kilowatts first.
= 1.5 kW
Read the steps as text
- Convert watts to kilowatts. 1,500 W ÷ 1000 = 1.5 kW Electricity is billed per kilowatt-hour, so watts are converted to kilowatts first.
- Find the energy used per day. 1.5 kW × 2 hours = 3 kWh A kilowatt-hour is the energy used by a 1,000-watt load running for one hour.
- Multiply by your electricity rate. 3 kWh × $0.1600/kWh = $0.480
- Project to a month and a year. $0.480 × 30 = $14.40 · × 365 = $175.20 Assumes the same daily usage every day — scale it down if it's only used some days.
How the running cost is worked out
Electricity is billed by the kilowatt-hour (kWh): the energy used by a 1,000-watt load running for one hour. To find the cost, the appliance's wattage is first converted to kilowatts, multiplied by the hours it runs each day to get the daily energy use, then multiplied by your electricity rate to get the daily cost. Multiplying that daily figure by 30 and 365 gives rough monthly and yearly projections.
If you only know an appliance's voltage and current rating rather than its wattage — common on some labels — switch to "I know volts & amps" and the calculator multiplies them together first (watts = volts × amps) before running the same calculation.
Finding your real electricity rate
The default rate here is only a placeholder. Your actual price per kWh is on your electricity bill, and it varies a lot by location, provider, and sometimes by time of day (some plans charge more during peak hours). Using your real rate instead of an estimate makes a noticeable difference for anything left running for long periods, like a fridge, water heater or air conditioner.
Getting a more accurate estimate
This calculator assumes the same usage every single day of the month and year. For something used only occasionally — a washing machine run three times a week, a space heater only in winter — the daily cost figure is still accurate for a day of use, but scale it by the actual number of days used instead of relying on the monthly or yearly numbers directly. Devices that cycle on and off automatically, like a fridge or an air conditioner's compressor, also don't draw their full rated wattage constantly, so their real running cost is usually somewhat lower than treating them as "always on" at full power would suggest.
Frequently asked questions
- How much does it cost to run a 1,500 W heater for 8 hours?
- At a typical rate of around $0.16 per kWh, about $1.92 for that day (1.5 kW × 8 hours × $0.16). Enter your own rate above for an exact figure — rates vary widely by location.
- What is a kilowatt-hour?
- The energy used by a 1,000-watt device running for one hour — it's the standard unit electricity is billed in, regardless of how quickly or slowly that energy is actually used.
- Where do I find my real electricity rate?
- On a recent electricity bill, usually listed as a price per kWh. Some plans also vary the rate by time of day, in which case an average rate gives a reasonable estimate.
- Does a fridge really cost this much to run 24 hours a day?
- Probably less — fridges and similar devices with a compressor cycle on and off rather than drawing their full rated wattage the whole time, so a calculation assuming constant full power tends to overestimate their real cost.
- How do I calculate cost if I only know the volts and amps?
- Switch to "I know volts & amps" above — the calculator multiplies them to get watts (watts = volts × amps) and uses that in the same cost calculation.