Electric Vehicle Efficiency Converter

Electric vehicle efficiency measures how much energy a car uses per unit of distance. Unlike gasoline cars (which use L/100km or mpg), EVs use energy metrics.

The core unit is Wh/km (watt-hours per kilometer):

• A smaller number means a more efficient vehicle (uses less energy per km)
• A larger number means more energy per km (heavier, less aerodynamic, or more powerful car)

Key conversion relationships:

• Wh/km → Wh/mile: Wh/mile = Wh/km × 1.60934
• Wh/km → km/kWh: km/kWh = 1000 ÷ Wh/km (they are reciprocals)
• Wh/km → miles/kWh: miles/kWh = 1000 ÷ (Wh/km × 1.60934)
• Wh/km → MPGe: MPGe = 33,705 ÷ (Wh/mile) — the US EPA formula

MPGe (Miles per Gallon equivalent): The US EPA defined 33.7 kWh as the energy equivalent of one gallon of gasoline. MPGe = 33,705 Wh ÷ Wh/mile

Typical EV efficiency ranges:

• Small/efficient EV (e.g., Tesla Model 3): ~140–165 Wh/km (3.5–5 miles/kWh, 130–135 MPGe)
• Mid-size EV (e.g., Rivian R1T): ~250–300 Wh/km (2.2–2.7 miles/kWh, 73–80 MPGe)
• Large EV truck/SUV: ~300–400 Wh/km (1.7–2.2 miles/kWh, 55–70 MPGe)
• Cold weather impact: EVs typically use 15–40% more energy in temperatures below 0°C (32°F)
• Highway vs city: Unlike gas cars, EVs are often more efficient in city driving due to regenerative braking

Comparing EV and gasoline cost per km:

• Average gas car (8 L/100km at $1.60/L) = $0.128 per km
• Average EV (160 Wh/km at $0.15/kWh) = $0.024 per km
• EVs are typically 4–6x cheaper to fuel per km in most countries