Energy Calculator
Electricity Cost Calculator
Estimate how much electricity a device uses and how much it may cost to run based on its wattage, operating time, and your electricity rate.
Your inputs
Estimate electricity cost
Enter the device's wattage, how long you use it, and your electricity rate. Results update automatically.
Look for watts (W) on the device label or manufacturer specifications.
Use the electricity rate from your utility bill when available.
Estimated results
Estimated monthly cost
$28.80
Based on the usage and electricity rate entered.
Daily cost
$0.96
Yearly cost
$345.60
Based on 12 months with the same number of usage days entered above.
Estimated energy use
- Per day
- 6 kWh
- Per month
- 180 kWh
- Per year
- 2,160 kWh
Calculation
Watts ÷ 1,000 × hours per day × days used × electricity rate.
How it works
How electricity cost is calculated
Electricity use is commonly measured in kilowatt-hours (kWh). To estimate the energy used by a device, first convert watts to kilowatts by dividing by 1,000, then multiply by the number of hours the device operates.
Daily energy use
(watts ÷ 1,000) × hours per day = kWh per day
Monthly energy use
kWh per day × days used per month = monthly kWh
Monthly electricity cost
monthly kWh × electricity rate = estimated monthly cost
Example calculation
Suppose a 1,500-watt device operates for 4 hours per day, 30 days per month, and electricity costs $0.16 per kWh.
Daily use: 1,500 ÷ 1,000 × 4 = 6 kWh
Monthly use: 6 × 30 = 180 kWh
Daily cost: 6 × $0.16 = $0.96
Monthly cost: 180 × $0.16 = $28.80
Yearly estimate: $28.80 × 12 = $345.60
Where to find your electricity rate
Your utility bill is generally the best place to start. Look for a rate expressed in dollars or cents per kilowatt-hour. Depending on your utility and rate plan, the price may vary by usage level, season, or time of day, and some bill charges may not be represented by a simple per-kWh rate.
For the most useful estimate, enter a rate that reflects the electricity pricing that applies to your household.
Keep in mind
This calculator provides an estimate.
Actual energy use can differ from a device's rated wattage because some equipment cycles on and off, changes power levels, or operates differently under different conditions. Your final utility bill can also include fixed charges, taxes, fees, tiered rates, time-of-use pricing, and other costs that this simple device calculation does not model.
Read our Disclaimer →Related guide
Trying to understand a high electric bill?
Our guide explains how to compare kWh, billing days, weather, HVAC use, appliances, and rate changes before assuming something in your home is broken.
Why Is My Electric Bill Suddenly So High?