Find what any appliance costs to run — enter its watts, hours a day and your price per kWh to get the cost per day, per month and per year in your currency. Runs entirely in your browser — your numbers never leave this device.
| Period | Energy (kWh) | Cost |
|---|---|---|
| Day | 6 | 1.50 |
| Month (year ÷ 12) | 182.5 | 45.63 |
| Year (365 days) | 2190 | 547.50 |
Costs are in whatever currency your rate is in — the calculator only multiplies energy by your rate. A month is a year (365 days) divided by 12.
Electricity is billed by the kilowatt-hour: one kilowatt drawn for one hour. An appliance's daily energy is therefore its power in kilowatts multiplied by the hours it runs — a 2,000 W heater used 3 hours a day uses 6 kWh a day — and the cost at any horizon is that energy multiplied by your price per kWh. This calculator shows the day, the average month and the year side by side, because appliances look cheap per day and surprisingly expensive per year, and the honest comparison between two appliances is usually the annual figure.
Two conventions are stated rather than hidden: a year is 365 days and a month is a year divided by 12, so daily, monthly and yearly figures are exactly consistent with each other. The rate is yours to enter from your own bill — use the all-in price per kWh including delivery and taxes if you want the true running cost, since tariffs differ by supplier, region and time of day and a built-in rate table would be wrong for most readers. For loads that cycle on and off, like fridges and air conditioners, enter average running hours rather than plugged-in hours, or use the maker's annual kWh figure divided by 365 as the daily energy.
Divide a recent bill's total variable charge by the kWh it billed, or read the unit rate from the tariff page of the bill. Use the all-in figure — energy plus per-kWh delivery and taxes — if you want the cost of running one more appliance, since that marginal kWh is billed at the full rate.
So the three horizons agree exactly: this page defines a year as 365 days and a month as a year divided by 12 (about 30.42 days). Multiplying the daily cost by 30 understates the year by five days; the average-month convention keeps day × 365 = year and year ÷ 12 = month with no drift.
Convert it first: watts = volts × amps for a resistive load. The Watts to Amps Converter on this site runs that in both directions, including three-phase and power factor — get the wattage there, then bring it back here for the cost.
Yes. The calculator never assumes a currency — it multiplies kWh by the rate you type, so the results are in dollars, pounds, rupees or any other currency your rate is in. Enter a rate of 30 and every cost is simply in that currency's units.
Standby is just a small always-on load: a device drawing 5 W on standby uses 0.005 × 24 = 0.12 kWh a day. Run it through the calculator at 24 hours a day to see the annual figure — standby is the clearest case where a trivial daily number becomes a real yearly one.
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