Estimate appliance energy use in kWh and its electricity cost from wattage, usage, and rate.
Nameplate power of the appliance (W). Check the label or manual.
Average daily run time. Include off-days as zeros for a true average.
Number of days in the period you want to cost (e.g., 30 for a monthly estimate).
Your per-kWh price — divide the supply portion of your bill by kWh used.
Energy Used
135.00 kWh
Total electrical energy consumed over the period.
Total Cost
$20.25
What you pay for that energy at your rate.
What this means
Converts instantaneous power and usage time into billable energy, then into money.
Estimate what an appliance costs to run by converting its wattage and usage time into kilowatt-hours, then multiplying by your electricity rate.
Formula
kWh = watts × hours × days ÷ 1000 | cost = kWh × rate
Worked examples
FAQ
How do I find my per-kWh rate?
Check your electricity bill: divide the supply portion of the bill by the kWh used, or use the rate your utility lists.
Should I include the days I do not use the appliance?
Set "hours per day" to the average daily use including off days for a steady monthly estimate.
Halve the hours, halve the cost — it is linear in every input. Efficiency gains show up directly in watts.