24 MPG combined isn’t great for the 2021 BMW M240i xDrive Convertible. However, many people buying this car want open-air thrills and the BMW inline-six engine sound more than ultimate fuel efficiency. This is a niche vehicle for a specific buyer, one who wants a reasonably compact, highly capable sports car and who will pay more at the pump to get it.

City and highway performance

The M240i xDrive Convertible’s EPA estimates are 21 MPG in the city and 30 MPG on the highway. The city figure reflects stop-and-go traffic, where the turbocharger spools up and the automatic transmission shifts. The highway number isn’t stellar because of the engine displacement and all-wheel drive, which adds weight and driveline friction. However, many owners report beating these official numbers on long highway runs, as the engine sits at low, fuel-efficient RPMs.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2021 BMW M240i xDrive Convertible at $2,400. This is based on driving 15,000 miles per year, with 45% in the city and 55% on the highway. The calculation also assumes national average fuel prices. Your fuel costs will vary depending on your driving habits, the type of fuel you use (premium is recommended for optimal performance), and where you live, but remember these figures are based on testing with regular-unleaded fuel.

Real-world expectations

While the EPA numbers are a useful benchmark, real-world fuel economy can vary. Aggressive driving, frequent short trips, and cold weather can negatively impact your MPG. On the other hand, smooth driving, minimal idling, and optimal tire inflation can help you get closer to, or even exceed, the EPA estimates. Also consider that convertibles encourage more spirited driving, further affecting miles per gallon. Check out M240I MPG across all years.

How it compares

Compared to other similar performance convertibles, the M240i xDrive lands in the middle. The Audi S5 Convertible, with its 3.0L V6, manages around 21 MPG combined. The Porsche 718 Boxster, with its turbocharged flat-four engine, gets slightly better mileage, at about 24 MPG combined in base form, but less power. Even within the BMW family, you’ll see variations. A 430i Convertible, with its 2.0L turbo four, offers significantly better fuel economy, around 28 MPG combined, but sacrifices performance. The buyer who selects the M240i is accepting a fuel economy trade-off, opting for the increased power and all-weather traction of xDrive knowing they could get better figures elsewhere.

Tips to maximize efficiency

While the M240i xDrive Convertible isn’t designed for Prius-like efficiency, there are a few things you can do to improve your fuel economy. First, avoid aggressive acceleration and braking. The instant torque of the turbocharger can be tempting, but smooth, gradual inputs will save gas.

Use the car’s driving modes. Comfort mode prioritizes fuel efficiency, while Sport and Sport+ modes sharpen throttle response and hold gears longer, consuming more fuel. Switch into Comfort for relaxed daily driving.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which burns more gas. Check your tire pressure and inflate them to the pressure indicated in the owner’s manual or on the door jamb sticker. Also, keep your convertible top up when possible as a more aerodynamic shape increases fuel economy.

Finally, keep up with scheduled maintenance. A well-maintained engine runs more efficiently. Replace air filters, spark plugs, and other components according to the manufacturer’s recommendations, which you can find alongside all Bmw fuel economy data. In the case of the M240i xDrive, keeping the car in peak running condition and using the correct premium fuel will translate directly to better MPG, in addition to overall performance gains.