GMC Acadia vs Subaru Outback: Specs Compared

Also searched as Subaru Outback vs GMC Acadia specs — both orientations show this same side-by-side comparison.

The Subaru Outback is the more efficient of the two: it reaches 29 mpg combined versus 25 mpg for the GMC Acadia, a 4 mpg advantage and costs about $350 less per year to fuel.

Across 5 measured categories, the Subaru Outback leads in 5. Figures are EPA test data, not manufacturer claims.

2015–2027

GMC Acadia

Standard Sport Utility Vehicle 2WD · 44 configurations

25mpg combined (best)
All GMC Acadia specs

2018–2027

Subaru Outback

Small Sport Utility Vehicle 4WD · 26 configurations

29mpg combined (best)
All Subaru Outback specs

Head-to-head specifications

MetricGMC AcadiaSubaru Outback
Best combined MPG25 mpg29 mpg ✓
Best city MPG22 mpg26 mpg ✓
Best highway MPG29 mpg33 mpg ✓
Lowest annual fuel costEPA estimate at 15,000 miles per year$2,450$2,100 ✓
Lowest CO2 output349 g/mi308 g/mi ✓
Engines offeredSIDISIDI, 2.5, 3.6
TransmissionsAutomatic 8-spd, Automatic 9-spd, Automatic 6-spdAutomatic (AV-S8), Automatic (AV-S7), Automatic (AV-S6)
DrivetrainsAll-Wheel Drive, Front-Wheel DriveAll-Wheel Drive
Fuel typesRegularRegular
EPA classStandard Sport Utility Vehicle 2WDSmall Sport Utility Vehicle 4WD
Years covered2015–20272018–2027
Configurations on record4426

Source: EPA fuel economy records via fueleconomy.gov. Best-case values across all recorded configurations for each model.

GMC Acadia vs Subaru Outback dimensions and size

The GMC Acadia is 12.2 inches longer than the Subaru Outback on a wheelbase 12.6 inches longer, and 535.7 lbs heavier. At over 200 inches, the larger of the two is past the comfortable limit of a standard 192-inch single garage bay once you allow walking room.

GMC Acadia versus Subaru Outback exterior dimensions
DimensionGMC Acadia (2026)Subaru Outback (2026)Difference
Length203.9 in191.7 in12.2 in
Width (excl. mirrors)79.5 in74 in5.5 in
Height70.9 in67.3 in3.5 in
Wheelbase120.9 in108.3 in12.6 in
Curb weight4,502 lbs3,966 lbs536 lbs

Width excludes mirrors; add 8–12 inches for mirrors out. Figures are for the newest model year on record for each vehicle. See both drawn to scale.

GMC Acadia vs Subaru Outback: what the numbers mean

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Subaru Outback burns about $2,100 of fuel annually against $2,450 for the GMC Acadia. That $350 yearly gap compounds to roughly $1,750 over five years and $2,800 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City and highway economy: the Subaru Outback leads in both cycles — 26 mpg city and 33 mpg highway against 22 and 29 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the GMC Acadia is recorded with 1 distinct engine configuration (SIDI), the Subaru Outback with 3 (SIDI, 2.5, 3.6). Across 44 recorded GMC Acadia configurations and 26 for the Subaru Outback, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the GMC Acadia is offered with All-Wheel Drive, Front-Wheel Drive, the Subaru Outback with All-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Standard Sport Utility Vehicle 2WD and Small Sport Utility Vehicle 4WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Subaru Outback emits 308 g/mile of CO2 versus 349 g/mile for the GMC Acadia. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.

Acadia vs Outback: common questions

Which is better on gas, the GMC Acadia or the Subaru Outback?

The Subaru Outback is the more efficient of the two: it reaches 29 mpg combined versus 25 mpg for the GMC Acadia, a 4 mpg advantage and costs about $350 less per year to fuel.

Which costs less to run per year?

By EPA estimates at 15,000 miles a year, the Subaru Outback runs about $2,100 a year in fuel at its most efficient configuration, versus about $2,450 for the GMC Acadia — a difference of roughly $350 per year.

What engines do the Acadia and Outback offer?

GMC Acadia: SIDI. Subaru Outback: SIDI, 2.5, 3.6.

Are they in the same vehicle class?

The EPA classifies the GMC Acadia as Standard Sport Utility Vehicle 2WD and the Subaru Outback as Small Sport Utility Vehicle 4WD, so they aren't a like-for-like match on size.

More Acadia comparisons

More Outback comparisons

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