‘Miles per kWh’ is the metric for electric vehicles that tells you how efficient they are. It’s the equivalent of miles per gallon (MPG) for traditional petrol or diesel vehicles. 4 miles per kWh is a high efficiency rating for an EV, and 2 miles per kWh would be a low rating. In a nutshell, a car's miles per kWh figure tells you how many miles it will travel on 1 kWh (1 unit of electricity stored in the car's battery). Read our “What’s the equivalent of MPG for an EV” Guide for a full description.