Cost Calculator AI
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EV Charging Cost Calculator

Calculate the cost to charge any electric vehicle at home or public DC fast chargers—accounting for battery pack capacity, session percentages, and charging efficiency losses.

Calculation Results

EV Charging Session Cost Formula

Session Cost = [ Battery Capacity (kWh) × (Target% − Current%) ÷ Efficiency ] × Electricity Rate ($/kWh)
  • Charging Efficiency Losses: AC Level 2 charging typically operates at ~88% efficiency due to onboard inverter heat losses; DC Fast charging operates at ~92% efficiency.
  • Grid Energy Consumed = Energy Stored in Battery / Charging Efficiency Factor.
  • Cost per Mile = Session Cost / Miles of Range Added.

Step-by-Step Worked Example

Scenario: Charging a 75 kWh battery from 20% to 80% at home ($0.16/kWh) with 88% efficiency

Calculation Steps:

  1. Net Battery Energy Needed = 75 kWh × 0.60 = 45.0 kWh
  2. Grid Energy Consumed = 45.0 kWh / 0.88 = 51.14 kWh
  3. Session Charging Cost = 51.14 kWh × $0.16 = $8.18
  4. Miles of Range Added = 310 miles × 0.60 = 186 miles
  5. Cost per Mile Added = $8.18 / 186 miles = $0.044 / mile (4.4¢ / mile)
Result: Adding 186 miles of range (20% to 80%) costs $8.18, or just 4.4¢ per mile.

How to Use This Calculator

  1. 1Enter your EV battery capacity in kilowatt-hours (kWh).
  2. 2Select starting and target battery percentages.
  3. 3Input your residential electricity rate or public charging rate ($/kWh).
  4. 4Optionally provide vehicle range to calculate cost per mile added.

Assumptions & Limitations

  • Assumes standard Level 2 home charging efficiency (88%) or DC fast charging (92–94%).

Frequently Asked Questions

Why should I only charge my EV to 80% on road trips?

Lithium-ion battery charging slows down dramatically above 80% to protect battery health and prevent overheating. Charging from 20% to 80% often takes 20 to 25 minutes, whereas going from 80% to 100% can take another 30 to 40 minutes.

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