22 MPG combined is not a figure that will excite everyone, nor should that be expected from a vehicle like the 2018 BMW 640i xDrive Convertible. This isn’t transportation designed for saving fuel. It’s a statement. It suggests weekend trips winding along the coast, of top-down motoring under a summer sky, and of a certain unapologetic indulgence. The fuel economy is simply the cost of entry.

City and highway performance

The EPA estimates 19 MPG in the city and 28 MPG on the highway for the 2018 BMW 640i xDrive Convertible, equipped with its 3.0L turbocharged inline-six engine and eight-speed automatic transmission. While the city figure might seem unremarkable, the highway number is surprisingly respectable for a car of this type. You can attribute it to the smooth-shifting transmission and relatively efficient engine, but understand that consistently achieving the highway estimate requires a disciplined right foot. The temptation of effortless speed is ever-present, and exercising restraint can be a challenge.

Annual fuel cost

According to the EPA, the annual fuel cost for the 2018 BMW 640i xDrive Convertible is $2,650. This figure is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that premium fuel is recommended for optimal performance, so this estimate assumes higher fuel costs than figures calculated using regular gasoline prices. Depending on your driving habits and local fuel prices, your actual fuel expenses may vary, but this provides a reasonable comparison.

Real-world expectations

While the EPA provides a useful standardized test, real-world fuel economy often differs. The 640i xDrive Convertible is particularly sensitive to driving style. Frequent bursts of acceleration, spirited cornering, and extended idling will all significantly reduce fuel economy.

Conversely, smooth acceleration, anticipating traffic flow, and mindful highway cruising can yield results closer to the EPA estimates. Don’t expect miracles, but a careful driver can certainly improve over the city MPG figure and occasionally match the highway estimate.

How it compares

In the realm of luxury convertibles, fuel economy isn’t typically the primary concern, but it’s worth knowing where the 640i xDrive Convertible falls. The contemporary Mercedes-Benz E450 Cabriolet, for example, achieves an EPA-estimated 23 MPG combined, placing it slightly ahead. A Porsche 911 Carrera Cabriolet, while having superior performance and a significantly higher price tag, achieves a similar 22 MPG combined, according to EPA estimates. Looking at Bmw fuel economy data, remember that driving style is important to achieving optimal highway mileage.