Mazda CX-90 vs Subaru Ascent: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Mazda CX-90 burns about $2,450 of fuel annually against $2,650 for the Subaru Ascent. That $200 yearly gap compounds to roughly $1,000 over five years and $1,600 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 Mazda CX-90 leads in both cycles — 24 mpg city and 28 mpg highway against 21 and 27 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Mazda CX-90 is recorded with 2 distinct engine configurations (SIDI; PHEV, SIDI; Mild Hybrid), the Subaru Ascent with 1 (SIDI). Across 9 recorded Mazda CX-90 configurations and 18 for the Subaru Ascent, 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 Mazda CX-90 is offered with 4-Wheel Drive, the Subaru Ascent 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 4WD and Standard 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 Mazda CX-90 emits 159 g/mile of CO2 versus 384 g/mile for the Subaru Ascent. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.