Mathematical Formulas & Engineering Modeling
At EVChargingCostCalculator.org, our calculations rely on transparent engineering formulas benchmarked against verified data from the U.S. Energy Information Administration (EIA), the U.S. Department of Energy Alternative Fuels Data Center (AFDC), and the EPA Fuel Economy Guide.
1. Grid Energy Consumption Formula
When charging an electric vehicle, the electrical energy drawn from the utility grid exceeds the net energy deposited into the battery cells due to alternating current (AC) to direct current (DC) conversion losses and thermal management overhead:
Grid Energy (kWh) = [Battery Capacity (kWh) × (Target SOC - Starting SOC)] ÷ Charger Efficiency (η)Where η is approximately 0.82 for Level 1 charging, 0.88 for Level 2 home charging, and 0.94 for high-voltage DC Fast charging.
2. Session Charging Cost
Session Cost ($) = Grid Energy (kWh) × Electricity Rate ($/kWh)3. Cost Per Mile & Cost Per 100 Miles
Cost Per Mile ($/mi) = Session Cost ($) ÷ Miles Added
Cost Per 100 Miles ($) = Cost Per Mile × 1004. Gasoline Equivalent Cost & Net Fuel Savings
Equivalent Gas Fuel Cost ($) = (Miles Added ÷ Gas Car MPG) × Gas Price ($/gal)
Net Session Savings ($) = Equivalent Gas Fuel Cost ($) - EV Session Cost ($)