EV Charging Cost Calculator
Estimate EV charging energy and cost from battery capacity, your charging-efficiency estimate, vehicle efficiency, electricity rate and fees.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Estimate in US dollars (USD). Enter charging efficiency as your estimated battery-energy/grid-energy ratio; actual losses vary by vehicle, equipment and conditions. Vehicle mi/kWh and electricity rate are inputs. Session costs exclude any fees you did not enter.
Worked example
calculated with the default values below
Battery capacity 75 kWh · Starting charge 20 % · Target charge 80 % · Electricity rate 0.17 USD/kWh · Charging efficiency (your estimate) 90 % · Charges per month 8 · Session or idle fee 0 USD · Vehicle efficiency 3.3 mi/kWh Cost per charge 8.50 USD · Energy added to the battery 45.00 kWh · Energy drawn from the grid 50.00 kWh · Monthly cost 68.00 USD · Electricity cost per 100 miles 5.72 USD
General background references
Disclaimer
These calculators give estimates for general information only. Real fuel consumption, performance and range vary with driving style, load, terrain, temperature and vehicle condition. Do not rely on these results for towing limits, payload or braking decisions — use the rating plate of your vehicle.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
C = B × (p_t − p_s) ÷ 100 ÷ η_c × r + f; C_100mi = 100 ÷ e ÷ η_c × r
- B
- Battery capacity (kWh)
- p_s
- Start charge (%)
- p_t
- Target charge (%)
- r
- Electricity rate (per kWh)
- f
- Session fee
- η_c
- Entered charging efficiency (fraction)
- e
- Vehicle efficiency (mi/kWh)
Use η ÷ 100 to convert the entered efficiency to a fraction. Grid energy = stored battery energy ÷ η. Actual charging losses vary; use measured or vehicle-specific data when available. Cost per 100 mi excludes session fees.
Frequently asked questions
How does the charging-efficiency estimate affect cost?
Grid energy equals the increase in battery energy divided by the efficiency percentage you enter. For example, adding 45 kWh at 90% efficiency estimates 50 kWh from the grid. Use measured or vehicle-specific data when available; the result excludes fees and taxes you do not enter.