EV Charging Cost Calculator (Maryland Electricity Rates)
Estimate how much it costs to charge your electric vehicle at home using Maryland's average residential electricity rates.
Total usable battery capacity of your EV (e.g., Tesla Model 3 Long Range = 75 kWh)
Your battery's current charge level before charging
Your desired charge level after charging
Typical Level 2 charger efficiency is 85–90%; Level 1 is ~80%
Maryland average residential rate ≈ 14.37 ¢/kWh (EIA, 2024). Check your bill for your exact rate.
How many times per month you perform this charge session
Formulas Used
1. Energy Added to Battery (kWh):
Energy to Battery = Battery Capacity × (Target SoC% − Current SoC%) / 100
2. Energy Drawn from Grid (kWh):
Energy from Grid = Energy to Battery ÷ (Charger Efficiency / 100)
3. Cost Per Session ($):
Cost = Energy from Grid × (Electricity Rate ¢/kWh ÷ 100)
4. Monthly Cost ($):
Monthly Cost = Cost Per Session × Charges Per Month
5. Annual Cost ($):
Annual Cost = Monthly Cost × 12
6. Cost Per Mile ($):
Miles Per Session = Energy to Battery × EPA Efficiency (3.5 mi/kWh)
Cost Per Mile = Cost Per Session ÷ Miles Per Session
Assumptions & References
- Maryland Average Residential Electricity Rate: 14.37 ¢/kWh (U.S. Energy Information Administration, EIA Electric Power Monthly, 2024 average for Maryland).
- Charger Efficiency: Level 1 (120V) chargers typically operate at ~80% efficiency; Level 2 (240V) chargers at 85–90%. Default is 85%.
- EPA EV Efficiency: 3.5 miles per kWh is used as a general average across popular EVs (e.g., Tesla Model 3, Chevy Bolt, Nissan Leaf). Actual efficiency varies by vehicle, speed, temperature, and driving style.
- State of Charge (SoC): Represents the percentage of usable battery capacity. Most manufacturers recommend charging to 80% for daily use to preserve battery longevity.
- Charger losses include heat dissipation and power conversion inefficiencies in the onboard charger and charging cable.
- This calculator estimates home charging costs only. Public DC fast charging rates vary significantly by network and location.
- Maryland electricity rates may vary by utility provider (BGE, Pepco, Delmarva Power, SMECO) and time-of-use (TOU) pricing plans.