Why is my gas mileage on my 2015 impreza 5-6 mpg below the rated mpg?

I usually get pretty close to the highway mpg number when driving with a very light foot. Our Infiniti will actually beat the highway number by 2 mpg. Subaru might need some break-in time. Maybe it will improve for you soon.

I owned a Honda Insight before this and always obtained the mileage the company told me it would get--so, never say never. 22/32 is the best I have obtained from the Subaru with very light foot driving. Thanks for the input. I did not expect the exact specified MPG but I did rather expect closer than this.

It is interesting than the closest iteration of the larger 2.5i, the Legacy Sedan w/ CVT, gets the same real world mpg as the smaller Imp's 2.0. My guess is that it's partially because the larger Leg's body actually has lower high speed drag. Conversely, the smaller Imp's 2.0 needs to rev up more to generate enough torque to overcome inertia at lower speeds. Another hint of this loss of efficiency (?) is that the 5speed manual Imp nearly matches the CVT efficiency, whereas this is definitely NOT the case with the manual trans 2.5i. Interesting, with one result that Subie's choice to use the underpowered 2.0 in the heavier CrossTrek version of the Imp is especially imprudent.

Did they find any cause for this? I just bought a used 2015 impreza and am extremely disappointed to be getting 21/22mpg.

Sounds like a pure city fuel eco. Try a highway driving test; you should see 34-36mpg at 65 mph.

I have a nearly new 2021 5door. Only have 2000 on it and it gets terrible miles per gallon. Less than twenty in town. May I expect it to get better as it breaks in?

See my answer above: perform a highway test calibration.

i have a 22 and i am noticing 21.5 mostly in town. i assume COLD and newness could be contributing factors, but a car this small getting 21 mpg is really bad. I am going to do a highway calibration check, but i'm going to take it in and ask subaru and start logging because this is so far below the estimate when it is not a crosstrek and sites lower to the ground. my 15 forester avg 24