EV Range vs. Charging Time Calculator
Estimate your electric vehicle's charging time and driving range based on battery capacity, charger power, and efficiency.
Total usable battery capacity of your EV (e.g. Tesla Model 3 LR ≈ 75 kWh)
Your battery's current charge level
Desired charge level (80% recommended for daily use to preserve battery health)
Level 1 ≈ 1.4 kW | Level 2 ≈ 7.2–19.2 kW | DC Fast ≈ 50–350 kW
Typical AC charging efficiency is 85–92%; DC fast charging is 92–95%
Average EV uses 250–400 Wh/mile (EPA combined). Check your vehicle's spec sheet.
Formulas Used
1. Energy to store in battery (kWh):
E_stored = Battery_Capacity × (Target_SoC − Current_SoC) / 100
2. Grid energy required (kWh):
E_grid = E_stored / Charger_Efficiency
Accounts for heat and conversion losses during AC→DC conversion.
3. Charging time (hours):
T = E_grid / Charger_Power
4. Range added (miles):
Range_added = (E_stored × 1000) / Energy_Consumption_Wh_per_mile
5. Total range at target SoC (miles):
Range_total = (Battery_Capacity × Target_SoC / 100 × 1000) / Energy_Consumption
6. Effective charging speed (miles/hr):
Speed = Range_added / T
Assumptions & References
- Charger efficiency of 85–92% is typical for Level 2 AC charging (SAE J1772); DC fast chargers achieve 92–95% (DOE, 2022).
- Energy consumption of 250–400 Wh/mile covers most EVs; EPA combined ratings are used as the standard benchmark (fueleconomy.gov).
- Charging to 80% is recommended by most manufacturers (including Tesla, GM, Rivian) to slow battery degradation and preserve cycle life.
- Cost estimate uses the US residential average electricity rate of $0.16/kWh (EIA, 2024). Actual rates vary by region and time-of-use tariff.
- This calculator assumes a constant charger output power. In practice, DC fast chargers taper speed above ~80% SoC.
- Battery capacity refers to usable capacity, which is typically 90–95% of gross capacity (manufacturers reserve a buffer).
- Range estimates assume flat terrain, moderate speed (~65 mph), and ambient temperature ~70°F. Cold weather can reduce range by 20–40%.