Calculate appliance electricity cost
Enter an appliance's power, daily use and your price per kWh to estimate its running cost. Compare one day, 30 days, 365 days and a period you choose.
Calculations run in your browser. The usage and prices you enter are not uploaded or stored by this tool.
How it works
- Enter the appliance's power in watts and its hours of use per day.
- Choose how many days to include in your selected period.
- Enter your electricity price per kWh in currency units: use 0.25 for 25 cents.
- Select a display currency, then read, copy or share the energy and cost estimates.
From watts to electricity cost
Energy in kWh = watts ÷ 1,000 × hours per day × days. Cost = kWh × price per kWh. A 1,000 W appliance running for 2 hours a day uses 2 kWh daily and 60 kWh over 30 days. At 0.25 currency units per kWh, that costs 0.50 per day or 15.00 for 30 days. The rate is an example, not a current utility tariff.
Use the right power and rate
A power label may show the maximum draw rather than the average. Refrigerators, heaters and other cycling appliances do not necessarily draw their rated wattage all day. For those appliances, use measured average power or estimate the time actually drawing that power. Enter the energy rate from your own tariff in currency units per kWh. This calculator does not fetch prices or convert currencies.
What the estimates include
All periods assume the same daily hours, power and flat energy price. The 30-day estimate is not a calendar month; the annual estimate uses 365 days. Fixed charges, tiered pricing, peak and off-peak rates, standby use, credits and taxes are excluded unless already reflected in your inputs. This estimates one appliance's energy cost, not your full electricity bill.
Supported inputs and rounding
Enter nonnegative numbers: up to 10 million watts, 24 hours per day, 36,500 days and 1 million currency units per kWh. Fractional hours and days are supported. Estimates above 1 trillion currency units in any displayed period are outside the calculation range. Energy displays up to four decimal places and money to two; calculations use unrounded values.
Worked examples
| Watts | Hours per day | Days | Price per kWh | Energy (kWh) | Cost (currency units) |
|---|---|---|---|---|---|
| 1,000 | 2 | 30 | 0.25 | 60 | 15.00 |
| 100 | 8 | 30 | 0.2 | 24 | 4.80 |
| 2,000 | 0.5 | 7 | 0.3 | 7 | 2.10 |
| 0 | 24 | 365 | 0.25 | 0 | 0.00 |
Frequently asked questions
How do I enter a rate shown in cents or pence?
Divide by 100 before entering it. For example, 25 cents per kWh becomes 0.25 dollars per kWh, and 30 pence becomes 0.30 pounds per kWh. Select the matching display currency.
Is a kilowatt the same as a kilowatt-hour?
No. A kilowatt measures power; a kilowatt-hour measures energy used over time. An appliance drawing 1 kW for 2 hours uses 2 kWh.
Can this calculate my whole electricity bill?
It estimates energy cost for the power, usage and flat rate you enter. Your bill may also include other appliances, standing charges, taxes, usage tiers or time-of-use prices that this tool does not calculate.
Does changing the currency convert the result?
No. It changes the display currency only. Enter the rate in that currency; no exchange rate is applied.
Sources
Last reviewed: November 7, 2026
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