Appliance Energy Cost Calculator

About this calculator

An appliance’s running cost is a direct product of its power draw, how long it runs, and your electricity rate: cost = (wattage ÷ 1000) × hours used × price per kWh. Dividing by 1000 converts watts to kilowatts, since utility bills are priced in kilowatt-hours (kWh) — the energy used by a 1000-watt device running for one hour.

This calculation is the basis of home energy audits, where households identify which appliances — often high-draw ones like electric water heaters, space heaters, air conditioners, and clothes dryers — are actually driving their electric bill, as opposed to low-power devices left on constantly, which add up less than intuition suggests. Utility companies and energy-efficiency programs publish calculators built on this exact formula to help customers decide whether upgrading to a more efficient appliance model is worth the investment.

Enter the appliance’s wattage, hours of use, and your electricity rate, and this calculator gives you its running cost.