EV Charging Time Calculator
Estimate how long it takes to charge your electric vehicle based on battery capacity, current charge level, and charger power.
Electric vehicle charging cost depends on your car’s battery capacity, current state of charge, charging equipment level, your electricity rate, and charging efficiency losses. Understanding these variables helps you budget accurately and compare EV costs to gasoline.
Formulas: Energy to Charge (kWh) = Battery Capacity × (Target% − Current%) ÷ 100 Actual Energy Drawn = Energy to Charge ÷ Charging Efficiency Charging Cost = Actual Energy Drawn × Electricity Rate ($/kWh) Cost per Mile = Charging Cost ÷ Miles Driven Miles of Range Added = Energy to Charge × Vehicle Efficiency (miles/kWh)
Charging levels:
| Level | Voltage | Max Power | Range Added/Hour | Typical Use |
|---|---|---|---|---|
| Level 1 (standard outlet) | 120V AC | 1.2–1.9 kW | 3–5 miles | Overnight, light drivers |
| Level 2 (home charger) | 240V AC | 7–19.2 kW | 15–65 miles | Home, workplace |
| DC Fast Charge (DCFC) | DC | 50–350 kW | 100–900 miles | Road trips |
Charging efficiency losses: Level 1 and 2 are approximately 85–90% efficient (AC to DC conversion generates heat). DC fast charging: 85–95%. Onboard charger and battery chemistry also affect efficiency.
Average US electricity rates (2024): $0.12–$0.18/kWh residential. Peak vs. off-peak rates: off-peak (midnight–6 AM) can be $0.07–$0.10/kWh in many areas.
Worked example: Tesla Model 3 (82 kWh battery, 4.0 miles/kWh efficiency). Currently at 20%, charging to 80% at home (Level 2). Electricity rate: $0.14/kWh. Charger efficiency: 88%.
Energy to charge = 82 × (80 − 20) ÷ 100 = 82 × 0.60 = 49.2 kWh Actual energy drawn = 49.2 ÷ 0.88 = 55.9 kWh Charging cost = 55.9 × $0.14 = $7.83 Miles of range added = 49.2 × 4.0 = 196.8 miles Cost per mile = $7.83 ÷ 196.8 = $0.040/mile
Comparison to gasoline: A 30 MPG gas car driving 196 miles uses 6.53 gallons × $3.50 = $22.87 EV cost: $7.83 — a 66% savings per trip.
Annual savings estimate: At 12,000 miles/year and $0.04/mile: EV cost = $480. Gas car at 30 MPG and $3.50/gallon: $1,400. Annual savings: $920.