Battery, energy & solar
Electricity Cost Calculator
Electricity cost equals energy used in kilowatt-hours multiplied by your price per kilowatt-hour. Daily, monthly, and annual estimates normalize the entered billing period.
Calculate electricity cost from energy use, billing-period length, and your own price per kilowatt-hour.
Calculated result
Estimated electricity cost
Calculating…
Calculated locally in your browser
Planning math only. Verify equipment specifications and installation requirements separately.
What this calculator returns
Use the effective rate from your bill if you want variable charges reflected; fixed charges require separate treatment.
Formula and variables
The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.
Cost = energy in kWh x price per kWh; daily, monthly, and annual estimates normalize the entered period by days.
- W
- Average real power in watts.
- h
- Operating or charging time in hours.
- kWh
- Accumulated electrical energy in kilowatt-hours.
- rate
- User-entered electricity price per kilowatt-hour.
- η
- User-entered efficiency expressed as a decimal or percentage.
Energy is measured in kilowatt-hours, rate is your planning price per kWh, and days is the measurement period.
Worked example
| Input | Value |
|---|---|
| Energy used | 900 kWh |
| Period length | 30 days |
| Electricity rate | 0.15 $/kWh |
| Result | Using 900 kWh over 30 days at $0.15/kWh gives a $135 period cost and about $4.50 per day. |
Using 900 kWh over 30 days at $0.15/kWh gives a $135 period cost and about $4.50 per day.
Reference table
| Use case | Energy | At $0.15/kWh | At $0.30/kWh |
|---|---|---|---|
| 1 kW for 1 hour | 1 kWh | $0.15 | $0.30 |
| 1.5 kW for 4 hours | 6 kWh | $0.90 | $1.80 |
| 30 kWh EV session | 30 kWh | $4.50 | $9.00 |
| 900 kWh billing period | 900 kWh | $135.00 | $270.00 |
Frequently asked questions
Is this electricity cost result code compliant?
No. PowerTotals performs transparent electrical math and planning estimates. Installation decisions must be checked against equipment documentation, the adopted code, and the authority having jurisdiction.
Are my inputs uploaded?
No. Calculations run locally in your browser, and analytics never receives raw electrical values.
Which electricity rate should I use?
Use the price per kWh that matches your purpose. An all-in effective rate can include variable bill charges, while a supply-only rate will not.
Assumptions and limitations
- No utility-rate database, tier, tax, demand-charge, or fixed-fee model.
- Monthly and annual values are normalized planning estimates.
Method and sources
Read the calculation methodology, review the technical sources, or browse the reference table index. Last reviewed .