How does the EV Charging Cost Calculator work?
The calculator finds the battery energy added from usable battery capacity multiplied by the change in state of charge. If you enter a charging-loss percentage, it estimates wall energy by dividing battery energy by one minus the loss rate. Wall energy is then multiplied by your electricity price per kilowatt-hour to estimate charging cost.
If vehicle efficiency in miles per kWh is entered, the tool also estimates the driving miles associated with the energy added to the battery. That is an energy-based estimate, not an official range prediction. For a battery-and-efficiency driving-distance scenario, use the EV Range Calculator.
Which electricity rate should you enter?
For home charging, use the marginal or applicable electricity rate from your utility plan when possible. Time-of-use plans can have different prices by hour, and some bills include fixed charges that do not change with one charging session. Public chargers may bill by energy, time, session or a combination, so enter an equivalent energy price only when that matches the pricing structure.
DOE’s Alternative Fuels Data Center notes that EV efficiency may be expressed as kWh per 100 miles and provides methods for estimating electricity cost per mile. If you want to combine charging with insurance, maintenance and other annual expenses, the Cost Per Mile Calculator can express those costs per mile.
Why include charging losses?
Not every kilowatt-hour drawn from the wall becomes stored battery energy. Power electronics, battery conditioning and other systems can consume energy during charging. The loss field lets you model this difference, but the real percentage varies with vehicle, charger, temperature and charging conditions.
If you do not have a reliable loss estimate, leave the field blank or zero and treat the result as battery-energy cost rather than a full wall-energy measurement.
What does this EV charging estimate leave out?
The result does not include charger installation, subscription fees, parking fees, demand charges, idle fees or battery degradation. It also does not know your utility tariff automatically. Vehicle value loss is also outside this tool; the Car Depreciation Calculator can model that separately. Use the actual rate and billing terms for your charging location. For a broader multi-year view of an EV’s expenses, compare the Vehicle Ownership Cost Calculator.
Frequently asked questions about EV Charging Cost
Battery energy added equals usable battery capacity multiplied by the increase in state of charge.
Charging systems can lose energy in conversion, battery conditioning and supporting electronics, so wall energy can exceed the energy stored in the battery.
Use the price per kWh that applies to the charging period or charging service you are modeling.
Yes. Enter 20 as starting charge and 80 as target charge.
No. Add fixed, time-based or parking fees separately unless you have converted them into an effective per-kWh price.
When entered, miles per kWh is multiplied by battery energy added to estimate the driving energy represented by the charge.
Not necessarily. Utility tariffs can include time-of-use prices, fixed charges and other billing rules.
The tool uses the usable battery capacity you enter. Vehicle battery management may reserve energy that is not shown as driver-usable capacity.
Sources and methodology
The calculator uses the formulas described on this page and user-entered assumptions. These authoritative U.S. resources provide context for the related vehicle, fuel, charging, finance or safety topic.