Electricity Cost Calculator
What an appliance costs to run, per day, month and year.
Quick answer
- Formula: kWh = Watts ÷ 1000 × hours; Cost = kWh × price per kWh
- Worked example — Energy used in the period: 15.00 kWh (full example below).
Electricity Cost Calculator
| Energy used in the period | 15.00 kWh |
| Cost per day | $0.08 |
| Cost per month (30 days) | $2.25 |
| Cost per year (365 days) | $27.38 |
A 100 W appliance running 5 hours a day uses 15 kWh in 30 days and costs $2.25 a month at $0.15/kWh.
Enter an appliance's wattage, how many hours a day it runs and your electricity price per kilowatt-hour. The calculator shows the energy used over your chosen period and what it costs per day, per 30-day month and per year.
Appliance labels often state maximum watts; real draw can be lower, especially for devices with motors or thermostats that cycle on and off. Use the figure as a solid estimate, not a meter reading.
The formula
Worked example
A 100 W appliance running 5 hours a day uses 15 kWh in 30 days and costs $2.25 a month at $0.15/kWh.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
Where do I find my price per kWh?
On your electricity bill: divide the total energy charge by the kWh used, or look for the stated supply rate. US residential averages are roughly 12–17 cents per kWh, varying by state.
How do I find an appliance's watts?
Check the label or plug plate — it may list watts directly, or volts and amps (watts ≈ volts × amps). A plug-in energy meter gives the most accurate real-world figure.
Category: Everyday Life calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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