The aim is to offer a method you can adapt to your own situation, not a one-size-fits-all answer. Gather relevant information, check assumptions and revisit the plan when something changes.

Convert watts to kilowatts

Electric bills usually charge for kilowatt-hours, abbreviated kWh. One kilowatt equals 1,000 watts. Multiply the appliance's kilowatts by the hours it runs to estimate energy used. A 1,200-watt device running for two hours uses 2.4 kWh before considering cycling or standby behavior.

Use your real rate

Find the energy rate on your bill and note whether it includes delivery or other per-kWh charges. A headline supply rate may not equal the complete marginal cost. Fixed monthly fees usually should not be added to the cost of one extra appliance unless allocating the whole bill.

Understand why actual use differs

A thermostat-controlled device may not draw rated power continuously. Refrigerators cycle, heat pumps change output and chargers vary by connected device. Nameplate wattage is a starting estimate; a suitable energy meter or utility data may give a better picture for compatible equipment.

Compare changes fairly

To estimate savings from a replacement, compare similar comfort, output and hours of operation. Consider purchase price, installation, maintenance and expected service life rather than energy cost alone. Savings depend on local rates, climate, usage and the condition of existing equipment.

Use estimates as a diagnostic

Choose one or two large or long-running loads to examine first. Keep a note of assumptions such as hours per day and rate per kWh. If the result is surprising, verify wattage, unit conversion and billing rate before making a purchase decision.

Quick checklist

  • Write down the values and units you are using.
  • Separate estimates from confirmed costs and requirements.
  • Check official, current information for final decisions.
  • Keep a record so you can update the estimate later.

Frequently asked questions

Does a 1,000-watt device always use 1 kWh per hour?

Only when it draws 1,000 watts continuously for that hour. Cycling devices use a different amount.

Does this include every item on my bill?

No. It estimates one load, not fixed fees, taxes, demand charges or all devices.

Try a related tool

Try the Appliance Electricity Cost Calculator →

This article is general educational information. It may not fit every location or individual circumstance. Verify current terms, rates, safety requirements and official guidance where applicable.