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Convert between electric vehicle efficiency metrics instantly
• Wh/mi = kWh/100mi × 10
• mi/kWh = 1000 / Wh/mi
• km/kWh = mi/kWh × 1.60934
• kWh/100km = kWh/100mi × 1.60934
| kWh/100mi | mi/kWh | Wh/mi | km/kWh | kWh/100km |
|---|---|---|---|---|
| 20 | 5 | 200 | 8.05 | 12.43 |
| 25 | 4 | 250 | 6.44 | 15.53 |
| 30 | 3.33 | 300 | 5.36 | 18.64 |
| 35 | 2.86 | 350 | 4.6 | 21.75 |
| 40 | 2.5 | 400 | 4.02 | 24.85 |
Kilowatt-hours per 100 miles (kWh/100mi) is a common electric vehicle efficiency metric in the United States, similar to L/100km for gasoline vehicles. It measures how much electrical energy an EV consumes to travel 100 miles. Lower values indicate better efficiency. Most modern EVs consume between 25-35 kWh/100mi.
Miles per kilowatt-hour (mi/kWh) is more intuitive for many people as it's similar to MPG - higher is better. The EPA also uses MPGe (miles per gallon equivalent), which compares EV efficiency to gasoline vehicles by using 33.7 kWh as equivalent to one gallon of gasoline. A car with 3 mi/kWh efficiency equals approximately 101 MPGe.
Wh/mi is often displayed on EV dashboards as it provides instant feedback on current efficiency. It's useful for understanding how driving conditions and style affect energy consumption. Typical values range from 200-400 Wh/mi, with lower values during highway cruising and higher values during city driving or acceleration.
European and Asian markets typically use metric efficiency measurements. Kilometers per kilowatt-hour (km/kWh) is similar to mi/kWh but uses metric distance. kWh/100km is the metric equivalent of kWh/100mi and is the standard in Europe. These conversions are essential for comparing EV efficiency ratings across different markets.
EV efficiency varies significantly based on speed, temperature, terrain, and driving style. Highway driving is less efficient than city driving for EVs (opposite of gasoline vehicles) due to aerodynamic drag. Cold weather reduces battery capacity and efficiency. Regenerative braking improves efficiency in stop-and-go traffic. Understanding these factors helps maximize your EV's range.
Good EV efficiency is typically 3-4 mi/kWh (250-333 Wh/mi or 25-33 kWh/100mi). Efficient EVs like the Tesla Model 3 achieve 4+ mi/kWh, while larger vehicles like the Rivian R1T get around 2 mi/kWh. Factors include vehicle weight, aerodynamics, tire efficiency, and powertrain design.
To calculate charging costs, multiply your distance traveled by your efficiency in kWh/mi (or kWh/100mi divided by 100), then multiply by your electricity rate per kWh. For example, 100 miles at 0.3 kWh/mi with $0.12/kWh electricity costs: 100 × 0.3 × $0.12 = $3.60. Home charging is typically cheaper than public fast charging.
Unlike gasoline vehicles, EVs are most efficient in city driving due to regenerative braking and no idling losses. Highway speeds increase aerodynamic drag exponentially (power required increases with the cube of speed), while regenerative braking can't recover energy during constant-speed cruising. EVs can lose 20-40% efficiency at highway speeds compared to city driving.
Cold weather significantly impacts EV efficiency, reducing range by 20-40% due to battery chemistry, cabin heating, and increased rolling resistance. Batteries perform optimally between 60-80°F. Using seat warmers instead of cabin heat, preconditioning while plugged in, and parking in garages can help minimize efficiency losses in cold weather.