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Electricity cost calculator
Convert known energy use in kWh into an estimated electricity cost. This is useful when your bill, meter, appliance estimate, or another calculator already gives you the kWh amount.
Convert kWh into cost
Use this when you already know the energy use in kWh and want to multiply it by your electricity rate.
How to use the result
This calculator is best when the kWh value is already known. That might come from a utility bill, a smart plug, a product estimate, or the Watts to kWh Calculator.
The same kWh-to-cost math can mean different things depending on the source of the kWh number. Use the result as a usage-cost estimate for that source, not automatically as the cost of one appliance or a full bill total.
| kWh source | What it usually means | How to use the result |
|---|---|---|
| Smart plug or meter reading for one device | Measured energy use for that device or setup | Treat the result as a usage-cost estimate for that measured period. |
| Electricity bill kWh for a billing period | Total energy use across the home for that bill period | Use it for broad usage-cost context, not as the cost of one appliance. |
| Watts and hours estimate converted to kWh | Estimated energy use from assumptions | Recheck runtime or wattage first if the result feels surprising. |
If the kWh came from a plug-in monitor, read how to measure appliance electricity use with a smart plug. If the kWh came from a bill, read how to read your electric bill for calculator inputs before mixing bill totals with usage-cost estimates.
If you still need to start from appliance wattage and daily runtime, use the Appliance Electricity Cost Calculator. For a short comparison, use the Electricity Cost Per Hour Calculator.
Measured energy use
If a smart plug reports that an air purifier used 7.2 kWh in one week, enter 7.2 as the kWh amount. At 0.20 per kWh, the estimated usage cost is 1.44 for that week.
This is different from starting with watts and hours because the energy use has already been measured. The result still estimates usage cost only, so compare bill-level items separately if you are matching it to a statement.
Formula
cost = kWh x electricity rate per kWh
For example, 12.5 kWh at 0.20 per kWh gives an estimated usage cost of 2.50 at that rate.
If your bill or meter shows 350 kWh for a period and your rate is 0.18 per kWh, the usage estimate is 63.00 in that same currency before bill-level items.
Limits
FAQ
Use this when you already know kWh. Use the appliance cost calculator when you need to start from watts and hours per day.
Yes. Enter the kWh for the billing period and the rate per kWh. Treat the result as usage-cost context, then compare bill-level items separately. If the final bill still looks higher than expected, read why your electric bill is higher than the calculator estimate.
Use the rate that applies to the kWh you are estimating, or run separate estimates for peak and off-peak rates.
Related tools
Choose the next calculator from the number you have now: watts, kWh, a one-hour check, or a full appliance-use estimate.
Home energy
What it shows
Convert appliance wattage and runtime into kWh so you can estimate energy use before working out electricity cost.
Best for
Turning an appliance label in watts into usable energy consumption over a chosen number of hours.
Home energy
What it shows
Estimate the daily, monthly, and yearly electricity cost of an appliance from its wattage, usage hours, and electricity rate.
Best for
Comparing the running cost of heaters, fans, computers, kitchen appliances, and other devices before you buy or leave them on every day.
Home energy
What it shows
Estimate how much an appliance costs to run for one hour, a typical 8-hour stretch, or a full 24-hour day.
Best for
Getting a quick hourly running-cost estimate before checking longer daily or monthly usage.
Site information
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