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D·02 · Energy and running costs

Electricity cost calculator for appliances

This electricity cost calculator works out what an appliance uses and costs to run: start from its watts and hours of use, or from the yearly kWh on its energy label.

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Electricity cost calculator: what an appliance costs to runMETER · ESTIMATED USE1,095kWh per yearPer day3 kWhPer month91 kWhPer year1,095 kWh

The meter shows kWh per year; below, per day, month and year, with the cost once you enter your price per kWh.

What to buy

Uses per year1,095 kWh
SHOPNAUTAElectricity cost calculator: what an appliance costs to run

Your measurements

Use1,000 W × 3 h × 7

1,095 kWh a year, 91 kWh a month

To buy

  1. 1Smart plug with energy monitoring
Per day3 kWh
Per month91 kWh
Per year1,095 kWh
Enter your price per kWh to see the cost

Estimate only: always go by what the product label says.

Estimate only: always go by what the product label says.

How to work out electricity use and cost

To go from watts to kWh, multiply the power in watts by the hours of use and divide by 1,000: a 1,000 W appliance running for 3 hours uses 1,000 × 3 ÷ 1,000 = 3 kWh. The calculator multiplies by the days of use per week and the weeks in a year, then splits the total by month and day. Enter your price per kWh and it adds the cost.

For appliances that do not run at full power all the time, like refrigerators and freezers, start from the energy label instead: it gives the yearly use in kWh from a standard test.

A worked example

The calculator opens with a 1,000 W appliance used 3 hours a day, every day.

  • Per day: 1,000 × 3 ÷ 1,000 = 3 kWh
  • Per month: 91.25 kWh
  • Per year: 1,095 kWh

At an example price of 0.30 per kWh that is 0.90 a day and 328.50 a year. Your real price is the one on your bill.

How much does it cost to run an air conditioner, a refrigerator or a space heater?

  • Air conditioner. On the spec sheet, look for the power input in cooling mode, in W or kW. It is not the cooling capacity in BTU: a 9,000 BTU unit delivers about 2.6 kW of cooling but draws far less from the outlet. Enter that power and your hours of use.
  • Refrigerator. Use the yearly kWh on the energy label (the yellow EnergyGuide label in the US): the compressor cycles on and off, so watts × 24 hours would overstate it by a lot.
  • Space heater. A resistive heater draws its rated power the whole time it heats, so watts × hours is a fair estimate: a 1,500 W heater for 5 hours uses 7.5 kWh.

Your price per kWh

The fairest price is your average: the bill total divided by the kWh you used in that period. That way it includes fixed charges, delivery and taxes, which the energy rate alone leaves out. The calculator has no built-in rates, because they change often.

Common mistakes

  • Mixing up watts and kWh. Watts are power, kWh are energy over time: 1,000 W for one hour is 1 kWh.
  • Using the AC's BTU as watts. BTU measure the cooling produced, not the electricity drawn.
  • Multiplying a fridge's wattage by 24 hours. The compressor does not run nonstop: use the label.
  • Forgetting standby. Devices left plugged in draw power even when off: a plug-in energy monitor shows how much.

Last reviewed: October 8, 2026 · About us