Household & Utilities
Estimate your monthly and yearly electricity costs based on appliance usage.
Monthly electricity cost
$33.75
225.0 kWh
Cost estimates are based on your inputs. Actual bills may vary due to seasonal rates, tiered pricing, taxes, and utility company fees.
An electricity cost calculator is a utility billing tool that estimates how much you spend on electricity for any appliance or device. It takes your appliance's power rating in watts, how many hours you use it each day, how many days per month you operate it, and your electricity rate per kilowatt-hour (kWh)—then multiplies these to show daily, monthly, and yearly costs. Unlike guessing, it accounts for real usage patterns and regional rate differences.
The calculator converts watts to kilowatts (divide by 1000), multiplies by daily hours to get kWh per day, scales to monthly usage (days per month), and multiplies by your electricity rate per kWh. The formula is: (Watts ÷ 1000) × Hours per day × Days per month × Cost per kWh = Monthly cost. Yearly cost is then 12 times the monthly value using a 30-day baseline month.
(Watts ÷ 1000) × Hours per day × Days per month × Cost per kWh = Monthly electricity costWatts is the appliance power. Dividing by 1000 converts to kilowatts (kW). Multiplying by hours per day gives daily kWh; multiplying by days per month gives monthly kWh. Finally, multiplying by cost per kWh (your utility rate) gives the cost in dollars. For yearly estimates, monthly cost is multiplied by 12 (using a 30-day baseline month).
| Input | Result | Notes |
|---|---|---|
| Microwave: 1000 W, 0.5 h/day, 30 days/month, $0.12/kWh | $1.80/month | (1000 ÷ 1000) × 0.5 × 30 × 0.12 = 15 kWh × $0.12 = $1.80 monthly. |
| Air conditioner: 3500 W, 8 h/day, 30 days/month, $0.15/kWh | $126.00/month | (3500 ÷ 1000) × 8 × 30 × 0.15 = 840 kWh × $0.15 = $126 monthly. |
| Electric heater: 1500 W, 6 h/day, 30 days/month, $0.18/kWh | $48.60/month | (1500 ÷ 1000) × 6 × 30 × 0.18 = 270 kWh × $0.18 = $48.60 monthly. |
Check your latest utility bill—it usually shows total kWh and total cost, making it easy to divide. Alternatively, call your utility or visit their website. Residential rates often range from $0.10 to $0.30 per kWh depending on region and season.
Look for a label on the back or bottom of the device; it often shows 'Watts' or 'W'. For computers and chargers, check the block label. If missing, search online for '[brand] [model] specifications.' As a rough guide, microwaves are ~1000 W, AC units ~3500 W, refrigerators ~600 W, and laptops ~60 W.
Your bill includes taxes, fees, standby power for all devices (not just one), and possibly tiered rates (higher cost for high usage). Utility bills also average multiple appliances running together. This calculator estimates one appliance at a time.
Yes, the formula is the same. However, commercial rates, demand charges, and power factor corrections complicate things. For rough estimates, use the standard calculation; for accurate figures, consult your utility or an electrician.
Not automatically—some utilities charge different rates at different times (peak vs. off-peak hours). To account for this, run the calculation separately for peak and off-peak hours and add the results.
A kilowatt-hour (kWh) is 1000 watts of power used for 1 hour. It's the standard unit utilities bill in. A 1000 W appliance running for 1 hour uses 1 kWh. Understanding kWh helps you compare appliance costs fairly.