BMW X5 vs Mercedes-Benz GLS-Class: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the BMW X5 burns about $2,900 of fuel annually against $3,600 for the Mercedes-Benz GLS-Class. That $700 yearly gap compounds to roughly $3,500 over five years and $5,600 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 BMW X5 leads in both cycles — 24 mpg city and 31 mpg highway against 20 and 24 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the BMW X5 is recorded with 4 distinct engine configurations (SIDI & PFI; Mild Hybrid, SIDI; PHEV, SIDI; Mild Hybrid), the Mercedes-Benz GLS-Class with 2 (SIDI; Mild Hybrid, SIDI). Across 61 recorded BMW X5 configurations and 35 for the Mercedes-Benz GLS-Class, 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 BMW X5 is offered with All-Wheel Drive, Rear-Wheel Drive, the Mercedes-Benz GLS-Class with All-Wheel Drive, 4-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 BMW X5 emits 130 g/mile of CO2 versus 414 g/mile for the Mercedes-Benz GLS-Class. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.