Kia Rio vs Toyota Prius Prime: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Toyota Prius Prime burns about $1,150 of fuel annually against $1,700 for the Kia Rio. That $550 yearly gap compounds to roughly $2,750 over five years and $4,400 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 Toyota Prius Prime leads in both cycles — 55 mpg city and 53 mpg highway against 33 and 41 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Kia Rio is recorded with 2 distinct engine configurations (1.6, SIDI), the Toyota Prius Prime with 2 (SIDI & PFI; PHEV, PHEV). Across 17 recorded Kia Rio configurations and 10 for the Toyota Prius Prime, 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 Rio is offered with Front-Wheel Drive, the Toyota Prius Prime with 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 Compact Cars and Midsize 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 Toyota Prius Prime emits 50 g/mile of CO2 versus 249 g/mile for the Kia Rio. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.