Fuel efficiency is becoming more and more important whether it is for a compact hatchback or a recreational vehicle, a luxury sedan or a commercial truck. The cost of conventional fuel is certainly a factor behind this increase in interest for these types of vehicles but the movement toward supporting environmentally friendly products has permeated even though auto market over the last decade. When you think of fuel efficient vehicles, you may think of gas or diesel powered vehicles that have high rates of miles per gallon. But “fuel” can encompass alternatives such as electricity. It is sometimes difficult to compare electricity powered vehicles with gas or diesel, but it is not impossible. Here are six most efficient vehicles cutting across different classes and sizes. Fuel efficiency for gasoline or petrol vehicles is measured in mpg (miles per gallon). For electric vehicles or hybrids, the equivalent mileage is calculated considering a conversion of the fuel economy using kWh/100 miles to get the mpg equivalent.

1. Among two-seaters, the Smart ForTwo Cabriolet with a 0.9 L, 3-cylinder Auto (AM6) engine running on premium gas will offer you a combined mpg of 35. The combined mileage takes into account fuel efficiency on city roads and highways.

2. Among mini compacts, you have the Fiat 500e featuring an A-1, 82 kW AC Induction EV engine offering a mpg of 112.

3.Among subcompacts you will get the best fuel efficiency in BMW i3 BEV running on a 60 Amp-hour battery featuring an A-1, 125 kW AC Induction EV engine. It offers an mpg of 124.

4.The Chevy Volt is the most fuel efficient among compacts. Sporting a 1.5 L, 4-cylinder Automatic (variable gear ratios) PHEV engine, it offers 77 mpg.

5.In midsize range, the best bet is the new Hyundai Ioniq Electric featuring an A-1, 88kW PMSM EV engine offering an mpg of 136.

6. The Honda Civic 5Dr is the best large vehicle. Sporting a 1.5 L, 4-cylinder, Automatic (variable gear ratios) engine, it offers 34 mpg.

Many of these vehicles come in variants that will have an influence on the fuel efficiency. It goes without saying that your driving style, how much you drive, and whether you travel mostly city roads versus highways, all have a bearing on the mileage capacity. The electric vehicles and fuel powered vehicles must not be compared at tandem owing to the plethora of differences they have in a multitude of configurations. However, if choosing a “green vehicle” is of most important to you, you can beat an electric vehicle. You may even want to explore alternate fuel vehicles like those powered by hydrogen and bio-fuels like ethanol. You’ll find yourself spending more upfront, but the savings from government incentives like purchase rebates and discounts on registration fees along with the accumulated savings on fuel might make it worth it.