Efficiency is graded within powertrain class

A Toyota Corolla can out-grade a Tesla Model 3 on Efficiency, and when it does the site is working correctly. That sentence is the reason this guide exists. Efficiency & Range is the one subject on MotorGPA normalized within powertrain class as well as within segment, and unless you know that, the grade looks broken.

MPG and MPGe are not the same number

An EV’s efficiency is reported in MPGe — the miles it travels on the energy in a gallon of gasoline, about 33.7 kWh. It is a useful figure and it is not comparable to MPG: a mid-size electric sedan posting 120 MPGe and a mid-size gas sedan posting 32 MPG are both ordinary for their kind, and neither number tells you anything about the other. Range has the same problem in reverse — a 300-mile range is unremarkable for a gas car and near the top of the class for an EV — and so does annual energy cost.

Score them all against one band and the EVs take every efficiency plaque forever, not because they are efficient for what they are but because the band was drawn for gasoline. That is what the site originally did, and it produced a real absurdity: a Model 3 with a 363-mile range scored 22 out of 100 on driving range, because the only band that existed was the gas one, drawn from 300 to 650 miles.

Four classes, each with its own bands

Every scorecard is graded as exactly one class: gas (diesel folds in), hybrid, plug-in hybrid or electric. The class is a property of the configuration the scorecard describes — the volume trim — not of the nameplate. A RAV4 nameplate offers a hybrid and a plug-in, but a scorecard is one car, and the class is the one it was scored as; it is printed beside the Efficiency grade everywhere the grade appears.

The economy, range and energy-cost criteria then carry one band per (class × segment). For sedans:

There are also criteria that exist only for some classes. Electric-only range is a plug-in hybrid criterion; DC fast-charge peak rate and 10–80% charge time are EV criteria; and the charge-time criterion is further gated on the car actually having DC fast-charge hardware, because a first-generation Fiat 500e is as much an EV as an Ioniq 5 and cannot fast-charge at all — for it the measurement is undefined rather than bad, and the framework omits it.

What the classes actually post

One winner per class

Because the grade is within-class, a fleet-wide “most efficient vehicle” is meaningless — it would always be whichever EV happens to post the biggest MPGe. So the Dean’s List on the homepage and the honor roll award Efficiency four times, once per class. In the current model year the plaques go to:

Reading the grade

An Efficiency grade says how a vehicle compares with others of its kind, in its segment. It does not say which powertrain to buy — that depends on your electricity price, your commute and your charging, and a B in the EV class can still cost a third as much to run as an A in the gas class. For that decision the car page prints the raw figures beneath the grade: the economy, the range and the estimated annual energy cost in dollars. The dollars are comparable across classes. The grades are not, and are not meant to be. It is also why Efficiency is kept out of the overall GPA; see How the overall GPA is weighted.