The electricity cost calculator estimates kilowatt-hours consumed and cost over a billing period from appliance power, daily use, and electricity rate. It accepts power in watts or kilowatts.
How to use this calculator
Enter rated or measured power and select its unit, then add daily operating hours, price per kWh, and days in the period. Watts are divided by 1,000 before calculating energy.
Formula & calculation method
Energy (kWh) = power (kW) × hours per day × days; cost = energy × rateA kilowatt-hour is one kilowatt used for one hour. The model assumes constant power during the entered operating time. Actual utility charges may include additional tariffs and fees.
Worked example
A 1,500-watt appliance is 1.5 kilowatts. Used three hours daily for 30 days, it consumes 135 kWh. At 0.20 per kWh, estimated energy cost is 27.00.
Why this is useful
Explicit watt/kilowatt conversion reduces a common billing error. Energy and cost outputs help compare appliances, usage habits, and different rate assumptions over the same billing period.
Limitations to keep in mind
Many appliances cycle or vary their power rather than running continuously at rated power. Tiered rates, taxes, standing charges, and demand fees are excluded, so the result may differ from a utility bill.
Frequently asked questions
Why divide watts by 1,000?
Because utility energy is billed in kilowatt-hours, and one kilowatt equals 1,000 watts.
Does rated power equal actual consumption?
Not always. Some devices use less or cycle on and off. A plug-in energy meter can provide a better usage estimate.
Are all utility charges included?
No. Only energy multiplied by your entered kWh rate is included, not fixed fees, taxes, or tier adjustments.