Formula
Energy charge = Kilowatt-hours * Energy rate per kWhDirect answer
Multiply the kilowatt-hours by the energy rate per kilowatt-hour. The U.S. Department of Energy notes that utility bills can have separate energy, demand and fixed components, so this calculator intentionally estimates only the entered energy-charge component.
Variables and formula
- Electricity use: kilowatt-hours for the chosen billing period or scenario.
- Energy rate: the energy-only price per kWh from the relevant tariff line.
- Billing days: days represented by the entered kWh, used for the daily and monthly projection.
Energy charge = Kilowatt-hours * Energy rate per kWh
Reproducible example
For 450 kWh at $0.16 per kWh, 450 * 0.16 = $72.00 for the estimated energy charge.
Interpretation
Compare the estimate with the energy line on a bill, not necessarily with the total due. A bill can include fixed, delivery, tax, demand or time-of-use components that this simple scenario does not model.
Assumptions and limitations
- The rate and kWh use the same tariff and billing period.
- The result does not predict future rates or usage.
- Fixed fees, taxes, credits and demand charges are excluded unless embedded in the entered rate.
Common mistakes
- Entering a total bill divided by kWh as if it were an energy-only rate.
- Mixing monthly kWh with a daily rate.
- Treating a flat-rate estimate as a time-of-use bill calculation.
Assumptions
- The entered rate is compatible with the entered kWh and period.
- The estimate covers energy charges only.
- Fixed fees, taxes, demand charges, credits and time-of-use rates are excluded unless reflected in the entered rate.
Sources and methodology
CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.
- Evaluating Your Utility Rate Options; U.S. Department of Energy; accessed Aug 3, 2026