The 2018 BMW X3 M40i gets 23 MPG combined, an acceptable figure for a compact performance SUV that drives like a sports sedan. This isn’t a Prius competitor, as buyers in this segment prioritize rapid acceleration, confident handling, and the practicality of a hatchback over ultimate fuel savings. They’re willing to trade a few MPGs for the driving experience BMW’s M division delivers in this size class.

City and highway performance

The X3 M40i’s EPA ratings are 20 MPG in the city and 27 MPG on the highway. The city figure reflects stop-and-go traffic where the turbocharged engine, even with its advanced efficiency technologies, consumes more fuel during frequent acceleration. The highway number is better, showing that when cruising steadily, the X3 M40i can achieve reasonable efficiency. The eight-speed automatic transmission is important here, keeping the engine in its most efficient rev range at higher speeds. Gently pressing the accelerator will certainly help you get closer to that 27 MPG target.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,500 for the 2018 BMW X3 M40i. This is based on driving 15,000 miles per year, with a mix of city and highway driving, using the national average fuel price. Fuel costs can vary significantly depending on how and where you drive. If you primarily drive in the city or drive aggressively, expect to spend more. However, if you mostly drive on the highway and drive efficiently, you might spend less. This $2,500 estimate provides a useful benchmark, but adapting it to your personal driving habits will give you a more accurate prediction.

Real-world expectations

EPA numbers provide a standardized baseline, but real-world fuel economy often differs. Drivers who frequently engage the X3 M40i’s Sport or Sport+ drive modes, or those who enjoy using the engine’s considerable power often, will likely see their fuel economy dip below the EPA estimates. However, those who primarily use the Comfort or Eco Pro modes and adopt a more relaxed driving style can potentially achieve fuel economy that matches or even slightly exceeds the EPA figures. The key is understanding your own driving habits and how they relate to the X3 M40i’s performance.

How it compares

The X3 M40i’s fuel economy compares reasonably well within its class. The Porsche Macan S, another performance-oriented SUV, gets around 19 MPG combined. The Mercedes-AMG GLC 43 offers similar performance and efficiency to the X3 M40i, with around 21 MPG combined. An Acura RDX with the standard 2.0L turbo manages better fuel economy, around 24 MPG combined, but offers less power and a less engaging driving experience. For those seeking a plug-in hybrid option in this segment, the Volvo XC60 Recharge offers significantly better fuel economy with its electric range, but at a higher price point. The balance between performance and fuel economy is always a consideration, and the X3 M40i balances it well for its target audience. For all BMW fuel economy data, compare it to the X3 MPG across all years to see if different engines or model years offer a better mix of power and efficiency.

Tips to maximize efficiency

Use the X3 M40i’s Eco Pro driving mode. This mode remaps the throttle response and transmission shift points to prioritize fuel efficiency. It encourages a more relaxed driving style and can significantly improve fuel economy, especially on longer trips. It’s not the most engaging mode for spirited driving, but it’s ideal for commuting or cruising on the highway.

Monitor your tire pressure. Underinflated tires increase rolling resistance, which hurts fuel economy. Check your tire pressure regularly and inflate them to the recommended levels, which can be found on the driver’s side doorjamb. Even a slight increase in tire pressure can make a noticeable difference over time.

Avoid idling. Letting the engine idle for extended periods consumes fuel unnecessarily. If you’re stopped for more than a minute or two, turn off the engine. Modern engines are designed to restart quickly and efficiently, so you won’t cause any harm. This is true with this vehicle’s start/stop system, which can be left active.

Minimize weight. Carrying extra weight in your vehicle reduces fuel economy. Remove any items you don’t need, such as shopping bags, sports equipment, or tools. The lighter your vehicle, the less fuel it will consume.

Use cruise control on the highway. Maintaining a consistent speed on the highway can improve fuel economy. Cruise control helps you avoid sudden acceleration and deceleration, which can waste fuel. Set it to a reasonable speed and let the system maintain it.