Energy
Turn appliance power, usage, and your electricity rate into a clear cost.
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Electricity cost calculator guide
Electricity cost is the price of the energy an appliance uses, not simply its wattage. This calculator starts with the appliance power rating, converts watts to kilowatts, multiplies by hours of use, and then applies your electricity rate. It shows the same estimate per hour, per day, per 30-day month, and per 365-day year so you can see how a small daily cost adds up. Use the rate from your electricity bill when possible. A label wattage is usually a maximum or nominal draw; refrigerators, air conditioners, heaters with thermostats, and other cycling devices may use less or more than a constant-watt assumption over time. For a quick comparison, enter a realistic average number of hours rather than the number of hours the device is available. This calculator estimates energy usage cost only; fixed charges, taxes, tiered pricing, demand charges, and delivery fees can make the final bill different.
Energy per day (kWh) = watts × hours per day ÷ 1,000. Cost = energy (kWh) × electricity rate. Monthly uses 30 days; annual uses 365 days.
Worked example with the defaults: a 1,000 W appliance used for 4 hours per day at $0.16 per kWh uses 1,000 × 4 ÷ 1,000 = 4 kWh per day. Daily cost is 4 × $0.16 = $0.64, and the per-hour row is 1 kW × $0.16 = $0.16. The 30-day estimate is $0.64 × 30 = $19.20, and the headline 365-day estimate the calculator displays is $0.64 × 365 = $233.60 per year. Halving the hours to 2 per day halves every line, so the annual figure would fall to $116.80.
Watts measure power; kilowatt-hours measure energy. Divide watts by 1,000 before multiplying by hours. Your rate must be currency per kWh, not a monthly bill total. The page uses 30 days for a month and 365 days for a year, so calendar billing periods may differ slightly. If the appliance label lists amps and volts instead of watts, multiply them together to get watts first.
This is a modelled estimate, not a meter reading. Real consumption moves with weather, occupancy, appliance age, standing charges, and tariff structure, and equipment rarely runs at its nameplate rating. Use the figure to compare options against each other, then confirm against your own bill and the manufacturer's specification before committing to a purchase. On this page the figure rests entirely on power, hours per day, electricity rate, market / jurisdiction, effective date, data source, update owner and review date, so start there if the electricity cost calculator returns something you did not expect.
Do not multiply watts directly by dollars per kWh; convert to kilowatts first, or the estimate will be 1,000 times too high. Avoid using the appliance’s full rated wattage when it cycles: a 1,000 W heater with a thermostat may average 400–600 W over an hour. Do not treat this estimate as your entire household bill unless you add every major load and the fixed charges, and do not enter a tiered or time-of-use rate as a single flat number without checking which tier your extra usage lands in.
Energy results depend on tariffs, equipment behavior, region, weather, and installation assumptions. Verify rates and electrical decisions with the utility, manufacturer, or qualified professional.
Sources
How it works
Turn appliance power, usage, and your electricity rate into a clear cost. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Power = 1000 W · Hours per day = 4 hours · Electricity rate = 0.16 $/kWh → $233.60 / year (estimated electricity cost). Change an input above and this example updates with your numbers.
Common questions
Multiply watts by hours used, divide by 1,000 to get kWh, then multiply by your electricity rate per kWh. For daily, monthly, or yearly costs, multiply by the number of days: 30 for a month and 365 for a year on this page.
At 4 hours per day and $0.16 per kWh, it costs about $0.16 per hour, $0.64 per day, $19.20 per 30-day month, or $233.60 per 365-day year. Devices that cycle on and off will usually cost less than this constant-draw figure.
Look for the energy charge on your utility bill, usually shown as a price per kWh. If your bill has tiers or time-of-use rates, use the rate that best matches the hours being estimated, or divide the total bill by total kWh for an all-in average.
A real bill can include fixed fees, taxes, delivery charges, tiered rates, demand charges, and other appliances. Actual appliance use can also vary because motors and thermostats cycle, so the label wattage is often higher than the average draw.
No. Wattage is the rate of power draw at an instant. A kilowatt-hour is energy used over time: 1,000 watts running for one hour equals 1 kWh, and 100 watts running for ten hours is also 1 kWh.