EV Charging Cost Calculator (United States)
Calculate wall energy, charge time, and per-session EV charging cost from battery size, state of charge, charger power, tariff, losses, and solar share.
Methodology reviewed August 25, 2026 by the Solar Calculator HQ editorial team. This is an editorial check, not professional engineering or tax certification. Review our formula, source and limitation standards.
EV Charging Calculator
The solar scenario assigns an opportunity cost of $0/kWh to the selected solar share. It does not model charging time against PV production or the export value you may give up.
What this calculator returns
The calculator reports:
- Energy delivered to the battery and energy drawn from the source
- An idealized charge time at constant entered power
- Grid-only session cost
- A simplified cost after the entered solar share
- The corresponding simplified solar saving
It does not produce an annual result. If you need one, calculate annual wall energy from vehicle efficiency and miles, then multiply by the tariff:
annual_wall_kWh = annual_miles × vehicle_kWh_per_mile / charging_efficiency annual_cost = annual_wall_kWh × tariff_per_kWh
The U.S. Department of Energy’s Alternative Fuels Data Center uses the same basic principle: charging cost depends on electricity price and the vehicle’s energy use. See DOE AFDC guidance on charging at home.
Inputs and defaults
| Input | Displayed default | Meaning |
|---|---|---|
| Battery capacity | 75 kWh | Usable capacity assumed by the scenario |
| Start / target | 20% / 80% | Change in battery state of charge |
| Charger power | 11.5 kW | Assumed constant wall-side power |
| Tariff | $0.16/kWh | Editable planning value, not the current national average |
| Solar share | 50% | Share of this session assumed to be supplied by solar |
| Efficiency | 90% | Battery energy divided by wall energy |
Use the tariff for the hours in which charging occurs. EIA’s May 2026 release reports a U.S. residential-sector average revenue of 18.44 cents/kWh, but a national monthly average is not a substitute for a household’s tariff. EIA Electric Power Monthly, May 2026 data.
Exact formulas
battery_energy_kWh = battery_kWh × (target_percent − start_percent) / 100 wall_energy_kWh = battery_energy_kWh / (efficiency_percent / 100) ideal_hours = wall_energy_kWh / charger_power_kW grid_cost = wall_energy_kWh × tariff_per_kWh solar_saving = grid_cost × solar_percent / 100 displayed_cost = grid_cost − solar_saving
The component clamps efficiency to 50%–100% and solar share to 0%–100%. It treats charger power as input power from the metered source. If a charger’s advertised kW is battery-side power, using it here can distort the time estimate.
Worked verification using the displayed defaults
For 75 kWh, 20% to 80%, 11.5 kW, $0.16/kWh, 50% solar and 90% efficiency:
- Battery energy = 75 × 0.60 = 45.0 kWh
- Wall energy = 45 / 0.90 = 50.0 kWh
- Ideal charge time = 50 / 11.5 = 4.35 hours, displayed as 4 h 21 min
- Grid-only cost = 50 × $0.16 = $8.00
- Simplified solar saving = $8 × 0.50 = $4.00
- Displayed cost after solar = $4.00
For a grid-only check, set solar share to 0%. For a public station, enter the station’s posted energy price only if billing is actually per kWh; session, idle, parking, membership and tax charges are outside the model.
Important limitations
- Battery capacity may be gross or usable depending on the manufacturer.
- AC Level 1 and Level 2 are limited by the lower of EVSE output and onboard-charger acceptance.
- DC fast charging is not constant-power and can taper materially.
- Weather and battery conditioning can change both wall energy and time.
- The tariff input does not handle tier blocks, demand charges, fixed fees or idle fees.
- Solar share is not calculated from PV size or clock time.
- The tool does not determine whether an electrical service, circuit or installation is suitable.
DOE advises checking vehicle specifications and local permitting requirements before installing home charging equipment. See DOE AFDC home-charging guidance.
Incentive date check
The calculator does not apply an EV-charger tax credit. IRS guidance states that Section 30C is not allowed for property placed in service after June 30, 2026. Eligibility before that date also depended on location and other requirements. See the IRS Public Law 119-21 FAQs.
Use the solar panel output calculator for a separate annual PV estimate and the solar cost calculator for an installed-cost scenario.
Sources
- DOE Alternative Fuels Data Center: Charging Electric Vehicles at Home — charging-energy, equipment and installation context
- EIA Electric Power Monthly Table ES1.A — source and period for the illustrative residential electricity price
- IRS Public Law 119-21 FAQs — Section 30C placed-in-service deadline
Frequently asked questions
How much does one EV charge cost?
Is $0.16/kWh the current U.S. residential average?
Does the calculator include charging losses?
Does the charge-time result match every vehicle?
How does the solar percentage work?
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