Understanding the Electricity Cost Calculator
An electricity cost calculator estimates what an appliance or device costs to run, based on its power draw, how long you use it, and your electricity rate. It turns the abstract kilowatt-hours on your bill into real dollars, helping you find which devices quietly drive up your energy costs.
Watts, hours, and your rate
Energy use is the device’s wattage multiplied by hours of use, converted to kilowatt-hours (kWh) and then by your rate per kWh. A 1,000-watt heater running for an hour uses 1 kWh. Devices that draw a lot of power or run constantly — heaters, air conditioners, water heaters — dominate most electricity bills.
Finding savings
Calculating per-device costs reveals where to focus. Sometimes the surprise is an always-on item like an old refrigerator or pool pump rather than the obvious big appliances. Knowing the numbers helps you decide whether upgrading to an efficient model, shifting use to off-peak hours, or simply unplugging idle electronics is worth it.
Tips & things to know
- •High-wattage or always-on devices dominate the bill.
- •Off-peak rates can make timing of use worthwhile.
- •An old, inefficient appliance can cost more than a new one to run.