Kia K4 vs Lexus UX: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Lexus UX burns about $1,450 of fuel annually against $1,800 for the Kia K4. 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 Lexus UX leads in both cycles — 45 mpg city and 41 mpg highway against 30 and 40 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Kia K4 is recorded with 3 distinct engine configurations (SIDI, 2.0, with DMS), the Lexus UX with 3 (SIDI & PFI; Hybrid, SIDI & PFI; Mild Hybrid, SIDI & PFI). Across 8 recorded Kia K4 configurations and 24 for the Lexus UX, 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 Kia K4 is offered with Front-Wheel Drive, the Lexus UX with All-Wheel Drive, Front-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 Midsize Cars and Compact Cars respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Lexus UX emits 204 g/mile of CO2 versus 264 g/mile for the Kia K4. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.