28 MPG combined makes the 2026 BMW M440i xDrive Convertible an efficient performance cruiser. This isn’t a four-cylinder economy car, nor is it a fully electric paradigm shifter. This is a 3.0-liter turbocharged straight-six, sending 382 horsepower to all four wheels, capable of dispatching 0-60 mph in under five seconds, all while offering the thrill of open-air motoring. For individuals who demand both exhilarating power and reasonable running costs, this 28 MPG figure represents a well-struck balance, defying the typical expectations of a luxury performance convertible.

City and Highway Performance

Looking at the numbers further, the M440i xDrive Convertible registers 25 MPG in city driving and 32 MPG on the highway. The city figure, 25 MPG, is particularly impressive for a vehicle of this caliber and weight, especially one equipped with an all-wheel-drive system. BMW’s excellent 8-speed Steptronic transmission, standard in this application, plays a significant role here, offering smooth shifts and intelligently selecting the optimal gear to keep the potent B58 engine within its most efficient operating range during stop-and-go scenarios. On the open road, stretching its legs, the 32 MPG highway rating shows the engine’s inherent efficiency. Cruising at highway speeds, even with the top down, the engine operates effortlessly, its broad torque band meaning less downshifting and more time spent in higher, more economical gears. This highway frugality is a primary reason why many all BMW fuel economy data buyers, individuals who frequently embark on weekend getaways or longer road trips, find this powertrain so appealing.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2026 BMW M440i xDrive Convertible at $2,050. This figure is calculated based on an average of 15,000 miles driven per year, using national average fuel prices. For a vehicle with its performance pedigree and luxury appointments, this $2,050 annual outlay is considerably less than what many might anticipate. The buyers of the M440i xDrive Convertible are typically professionals or established enthusiasts who appreciate performance but are not immune to financial considerations. While the initial purchase price is substantial, the ongoing running costs, specifically fuel, remain a relevant detail. This relatively modest annual fuel cost means more disposable income for other pursuits, perhaps enhancing the ownership experience with premium detailing, track days, or simply enjoying the finer things in life without constantly fretting over the fuel gauge. Spirited driving doesn’t have to equate to astronomical expenses at the pump.

Real-World Expectations

In real-world driving conditions, the 2026 M440i xDrive Convertible generally lives up to its EPA ratings. BMW has a reputation for delivering on its efficiency promises, and the B58 engine, a marvel of modern engineering, is a significant contributor to this consistency. Those who drive with a heavier foot, frequently exploring the upper reaches of the tachometer or making repeated hard accelerations, will naturally see figures closer to the lower end, perhaps dipping into the low 20s in aggressive city driving.

However, for the majority of owners who appreciate the car’s dynamic capabilities but also engage in composed cruising, particularly on longer journeys, 30+ MPG on the highway is a genuinely achievable benchmark. The mild-hybrid system, integrated into the car, also contributes to real-world savings, particularly in stop-start traffic, where it can recover energy and boost efficiency during acceleration. This car provides phenomenal performance without constantly feeling penalized by fuel stops.

How It Compares

When placed alongside its primary rivals, the M440i xDrive Convertible holds its own remarkably well in terms of fuel economy. Consider the Mercedes-AMG C43 Cabriolet, a direct competitor often cross-shopped by this segment of buyer. The AMG C43, with its 3.0-liter biturbo V6, typically delivers around 21 MPG combined (19 city/26 highway). The BMW’s 28 MPG combined represents a significant advantage, translating to tangible savings over the ownership period. Another contender, albeit with a slightly different character, is the Audi S5 Cabriolet. The S5, powered by a 3.0-liter turbocharged V6, usually achieves around 23 MPG combined (20 city/28 highway). Again, the M440i MPG across all years clearly outperforms both, solidifying its position as a class leader in efficiency. This superior fuel economy, without sacrificing outright performance or luxury, offers a strong argument for the M440i xDrive Convertible buyer, who values efficiency without wanting to compromise on the driving experience or brand prestige.

Tips to Maximize Efficiency

While the M440i xDrive Convertible is inherently efficient, conscious driving habits can further enhance its fuel economy. Gentle acceleration and anticipation of traffic rather than aggressive braking will significantly reduce fuel consumption, especially in urban environments. The responsive powertrain makes it easy to accelerate smoothly without feeling sluggish.

Use the vehicle’s driving modes effectively. While Sport or Sport+ modes are thrilling, Comfort or Eco Pro modes optimize engine and transmission parameters for maximum efficiency, ideal for highway cruising or relaxed city driving. The car is designed to be versatile, so use its intelligent systems.

Maintain consistent tire pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder. Check your tire pressure regularly, especially before long journeys, to ensure optimal efficiency and safety.

Avoid unnecessary weight in the boot or rear seats. Every extra pound the car carries requires more energy to move. While a small factor, removing items that aren’t truly needed can contribute to marginal gains over time.

Plan your routes to avoid excessive idling. If you know you’ll be stopped for an extended period, the automatic start-stop system will help, but minimizing unnecessary stops and starts through efficient route planning is always beneficial for fuel economy.