The Honda Civic has always been one of the most fuel-efficient vehicles in its class, and the latest Civic is no exception. Despite a hefty round of changes throughout the Civic line, and a little bit of added weight (50 to 80 pounds worth, fuel economy for the 2013 Civic hasn't changed versus last year.
EPA ratings for most of the lineup are at 28 or 29 mpg in the city and up to 41 on the highway--so the Civic actually gets better mileage than the smaller Honda Fit.
Actually, there is one exception in the lineup: The Civic Si, with its larger 2.4-liter engine and lower gear ratios, it's significantly thirstier than a V-6 Accord, especially if you tend to do mostly highway driving.
For maximum gas mileage, though, there's the Civic Hybrid model, now in its third generation and reworked to be even more fuel-efficient than before. Its EPA ratings are 44 mpg on both city and highway cycles, and it provides more boost than in pre-2012 form, from a larger 15-kilowatt (20-hp) electric motor.
Additionally there's an HF model--the key to that highest (for the non-hybrids) 41-mpg highway rating. It gets special low-rolling-resistance tires, plus some extra aerodynamic measures like underbody panels, a rear spoiler, and special smooth alloy wheels.
In real-world driving, from our observations, the Civic Hybrid is very impressive. Over nearly 400 miles of driving—leaving the car mostly in 'Econ' mode—we averaged more than 45 mpg. As for the other models, we managed to about match the EPA city number in mostly city driving.
Nearly all Civics come with an 'Econ' button on the left side of the instrument panel; the mode, when engaged, provides a gentler throttle setting, along with more conservative transmission behavior and accessory operation. It even softens cruise-control responsiveness to save fuel.