Electricity Cost Calculator
Calculate appliance electricity costs and monthly bills based on wattage, usage hours, and electricity rates with detailed cost breakdowns. Perfect for energy budgeting and appliance comparison with precise consumption analysis.
Check your appliance's manual or label for wattage rating
Check your electricity bill for your rate
Complete Guide: Electricity Cost Calculator
Everything you need to know about using this tool effectively
This electricity cost calculator determines how much it costs to run an appliance based on its wattage rating, daily usage hours, and your electricity rate per kilowatt-hour. The formula is cost = (wattage * hours * days / 1000) * rate. Results show daily, monthly, and annual costs along with total energy consumed in kWh.
The calculator converts wattage to kilowatts by dividing by 1000, then multiplies by usage hours and billing days to get total kilowatt-hours consumed. That kWh value is multiplied by your local electricity rate to produce the cost. A multi-appliance mode lets you stack several devices to see combined household or office energy expenses. A built-in appliance database stores typical wattage values for refrigerators, TVs, computers, lights, and other common devices so you can estimate costs even if you do not have the exact wattage handy.
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Find Your Rate
Check your utility bill for the cost per kWh. If you cannot find it, use the national average of about 0.13 dollars per kWh as a starting point.
Enter Appliance Wattage
Type the wattage rating from the appliance label or select a preset from the built-in database.
Enter Usage Hours
Estimate how many hours per day the appliance runs. Some devices cycle on and off, so use an average.
Set Billing Period
Choose 30 days for a monthly estimate or 365 days for an annual estimate.
Click Calculate
Review the daily, monthly, and annual cost along with total kWh consumed. Add more appliances if needed.
Check appliance labels or manuals for wattage. If only amps are listed, multiply amps by 120 volts (US) or 230 volts (EU) to get watts.
Many devices draw standby power when turned off. Add 5 to 10 percent to your estimate to account for phantom loads.
Electricity rates often change seasonally. Use the rate from your most recent bill rather than an annual average for more accurate projections.
Run the multi-appliance comparison to find which devices cost the most. Often HVAC and water heaters dominate the bill.
For appliances with variable power draw like refrigerators, use the manufacturer's stated annual kWh consumption instead of the rated wattage.
How is electricity cost calculated?
Cost equals wattage times hours of use divided by 1000 times the rate per kWh. A 100-watt bulb running 8 hours at 0.13 dollars per kWh costs 0.104 dollars per day, or about 3.12 dollars per month.
Where do I find my electricity rate?
Your rate appears on your utility bill under a label like 'energy charge' or 'rate per kWh.' US households typically pay between 0.08 and 0.20 dollars per kWh depending on location and provider.
Why does my calculated cost differ from my actual bill?
Bills include extra charges like distribution fees, taxes, demand charges, and tiered rates. This calculator covers only the energy consumption portion of your bill.
Can I use this for commercial three-phase equipment?
This calculator is designed for single-phase residential loads. Three-phase equipment requires power factor adjustments and different formulas. Consult an electrician for commercial calculations.
What is the difference between watts and kilowatt-hours?
Watts measure instantaneous power draw. Kilowatt-hours measure energy consumed over time. Running a 1000-watt appliance for one hour consumes exactly 1 kWh.