Electricity Cost per Month
Project the monthly cost of running any appliance by combining its wattage, daily usage, and your utility rate per kilowatt-hour.
Examples
- 1,200 W space heater × 3 h/day × $0.18/kWh ⇒ $19.44 per month
- 75 W refrigerator × 24 h/day × $0.12/kWh ⇒ $6.48 per month
- 10 W LED bulb × 5 h/day × $0.22/kWh ⇒ $3.30 per month
FAQ
Why does the formula divide by 1,000?
Electric utilities bill in kilowatt-hours. Dividing wattage by 1,000 converts watts to kilowatts before multiplying by time and rate.
How many days per month does the calculator assume?
It multiplies by 30 days. Adjust the daily hours or wattage if you want to account for fewer usage days.
Can I enter fractional hours or costs?
Yes. Use decimals for partial hours per day or rates like $0.183 per kWh for precision.
How do I include multiple appliances?
Run the calculation for each device and add the monthly amounts to estimate total household consumption.
Additional Information
- Monthly cost equals wattage ÷ 1,000 to get kilowatts, multiplied by hours of use, days per month, and your price per kWh.
- Average residential rates vary widely by region—check your latest bill or utility portal for the most accurate number.
- For devices with standby consumption, include both active and idle wattage to capture true monthly impact.
- Multiply the result by 12 to estimate annual expense and compare alternatives like Energy Star appliances.