Materials & quantities
Electricity Cost Calculator
Estimate energy cost from device power, operating time, and the user's electricity price.
Use this for a device-level estimate with your own tariff and schedule; it is not a utility bill forecast.
What the result means
The estimate converts watts to kilowatts, multiplies by hours, and applies your supplied price. Standby draw and tariff tiers may change a real bill.
The formula
(Power watts * hours / 1000) * price per kWh
Results are displayed to at most two decimal places. Calculations use the unrounded inputs.
A worked example
Put the formula to work
- Device power (watts)
- 1,000
- Operating time (hours)
- 10
- Electricity price (currency per kWh)
- 0.25
Estimated energy cost (input currency): 2.50
A 1,000 watt device for ten hours uses 10 kWh; at 0.25 per kWh the estimated cost is 2.50.
How to use this calculator
- Read or measure device power.
- Choose the operating period and hours.
- Enter your own price per kWh.
- Multiply energy use by price and compare with the bill's tariff scope.
Why this number matters
The conversion is transparent and user-specific, avoiding a made-up electricity rate or usage schedule.
Input definitions
- Device power (watts)
- Rated or measured device power in watts.
- Operating time (hours)
- Total operating hours for the chosen period.
- Electricity price (currency per kWh)
- Your applicable price per kilowatt-hour; enter taxes or fees only if you intend to include them.
Assumptions and limitations
- Rated power may not equal actual average draw.
- Taxes, fixed charges, tiers, time-of-use rates, and standby consumption may be outside the estimate.
- The result is not a utility billing or efficiency guarantee.
Methodology
The default result and worked example use the same calculation functions as the interactive tool. The formula cannot verify the quality or scope of your source data.
Read our calculation methodology
Last updated .