19 MPG combined won’t make the 2025 BMW M850i xDrive Convertible a fuel-sipping champion. However, for drivers who prioritize open-air thrills, a V8 rumble, and attention-grabbing style over saving gas, it’s an acceptable trade-off. This isn’t a car for bargain hunters; it’s for those who understand that a certain level of indulgence comes with the territory.

City and highway performance

The 2025 M850i xDrive Convertible gets an EPA-estimated 17 MPG in the city and 24 MPG on the highway. These figures are determined by the strong 4.4-liter eight-cylinder engine and standard all-wheel drive. The city number reflects the stop-and-go realities of urban driving, where the engine’s considerable power is often limited by traffic.

The highway figure improves significantly, allowing for more efficient cruising at consistent speeds. The eight-speed automatic transmission helps keep the engine performing well, balancing performance and relative efficiency, though the emphasis is definitely on performance. With 523 horsepower, resisting the urge to tap into its reserves will be a challenge.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2025 BMW M850i xDrive Convertible to be $3,050. This figure is calculated based on driving 15,000 miles per year, using national average fuel prices (based on the fuel type required by the vehicle). Keep in mind that this is just an estimate. Your actual fuel costs will vary depending on your individual driving habits, the type of fuel you use, and any fluctuations in fuel prices. However, $3,050 provides a solid benchmark against which to compare the M850i convertible to other vehicles in its class.

Real-world expectations

While the EPA provides a standardized benchmark, real-world fuel economy can vary. Aggressive acceleration, frequent use of Sport mode (which holds gears longer and blunts throttle response), and prolonged idling will all negatively impact fuel efficiency. However, consistent highway driving at moderate speeds should yield numbers closer to, or potentially even slightly exceeding, the EPA’s 24 MPG estimate.

The M850i’s driving dynamics are such that resisting the temptation to exploit its performance potential will require a conscious effort, and few owners likely buy this car to hypermile.

How it compares

The M850i xDrive Convertible exists in a specialized segment, but comparisons will be made. The Mercedes-AMG SL 55 Roadster, another powerful V8 convertible, achieves similar EPA estimates of 16 MPG city and 24 MPG highway. An Audi S5 Cabriolet, with its smaller V6 engine, manages better fuel economy around 21 MPG combined. These figures demonstrate the trade-offs: while the Audi offers better fuel efficiency, it lacks the raw power and prestige of the BMW and Mercedes.

For those considering other BMW options, exploring all Bmw fuel economy data could reveal more economical alternatives. Buyers in this category are less concerned with absolute fuel efficiency and more focused on the overall driving experience and ownership. Those seeking alternative years of this model should consider checking M850I MPG across all years.

Tips to maximize efficiency

The most effective way to improve fuel economy in the M850i is to adopt a smoother driving style. Avoid abrupt acceleration and hard braking, anticipate traffic flow and maintain a consistent speed whenever possible. These simple adjustments make a surprising difference.

Regularly check tire pressures to ensure they are at the recommended levels. Properly inflated tires reduce rolling resistance, which translates to improved fuel economy and prolonged tire life. Tire pressure monitoring is standard on the M850i, adding to easier maintenance of optimal pressure

Minimize idling time. Idling consumes fuel without covering any distance. If you anticipate being stationary for more than a minute or two, turn off the engine. The M850i uses start/stop technology at traffic lights, assisting in this saving, but this does not engage in all circumstances.

Consider using the adaptive driving modes. These settings adjust various vehicle parameters, including throttle response and transmission behavior, to prioritize fuel efficiency. While the temptation to live in Sport mode is strong, using Comfort in steady-state cruising can yield noticeable improvements.

Ensure that the vehicle’s maintenance schedule is followed. A well-maintained engine runs more efficiently, and regular servicing can catch potential issues that might negatively impact fuel economy before they become significant problems and can save money.