24 MPG combined for the 2026 BMW 840i Gran Coupe 3.0L 6-cyl is exactly what’s expected, as BMW engineers balance performance with usable efficiency in a premium luxury sport sedan. This car is not designed for hypermiling, nor for drivers whose main concern is saving every last drop of fuel. Instead, the 840i Gran Coupe suits buyers who appreciate the smooth delivery of the B58 inline-six, its refined cabin, and its striking looks, while still expecting good fuel economy for a car of its size, power, and purpose. This is a grand touring machine, built for covering long distances in comfort and style, and its 24 MPG combined rating perfectly aligns with that, offering a practical aspect to its aspirational appeal. For a deeper look at all BMW fuel economy data, our archives provide extensive information.

City and highway performance

Breaking down the 840i Gran Coupe’s EPA figures reveals a 21 MPG city rating and a 29 MPG highway rating. The 21 MPG in city driving is good for a vehicle of this type, operating with the start-stop demands of urban environments. BMW’s integration of the automatic (S8) transmission is expertly tuned, working with the 3.0L inline-six to maximize efficiency through lower RPM operation whenever possible, without ever feeling sluggish. The highway figure of 29 MPG is particularly impressive, showing the efficiency of the B58 engine when cruising. On open roads, this powertrain settles into a relaxed rhythm, its torque curve making light work of inclines and overtakes, often requiring minimal throttle input. This highway performance highlights the 840i Gran Coupe’s role as an excellent long-distance cruiser, providing comfort and a sensible fuel consumption rate for extended journeys.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,400 for the 2026 BMW 840i Gran Coupe 3.0L 6-cyl. This figure is based on driving 15,000 miles per year at national average fuel prices, reflecting typical consumer usage patterns. For the buyer of an 840i Gran Coupe, a vehicle with an MSRP well into the five figures, this annual fuel expenditure is generally perceived as a reasonable operational cost, not a deterrent. Owners of this vehicle prioritize the driving experience, the luxury amenities, and the sheer presence of the 8 Series Gran Coupe. The $2,400 annual cost represents a minor fraction of the overall ownership experience, which includes depreciation, insurance, and maintenance, factors that these buyers understand and accept as part of owning a premium BMW. For more on 840i MPG across all years, our dedicated model page has everything you need.

Real-world expectations

In real-world driving, owners of the 2026 BMW 840i Gran Coupe 3.0L 6-cyl can reasonably expect to achieve figures very close to the EPA estimates. BMW’s engine management is very advanced, and the B58 engine is known for its consistent efficiency. Aggressive driving with frequent use of the Sport mode and heavy throttle inputs will naturally see city figures dip closer to the high teens, while a disciplined driver on a long highway journey could easily touch, or even slightly exceed, the 29 MPG highway rating. The vehicle’s character encourages smooth, flowing movement rather than erratic acceleration, which helps maintain fuel efficiency. Those who primarily use their 840i Gran Coupe for daily commutes in moderate traffic will likely find their combined average hovering comfortably around the 24 MPG mark.

How it compares

When placed alongside its direct competitors, the 2026 BMW 840i Gran Coupe’s 24 MPG combined rating holds its own, often besting or matching rivals while offering a distinct driving experience. Consider the Mercedes-Benz CLS 450 4MATIC, which achieves an identical 24 MPG combined (22 city/30 highway) from its own mild-hybrid inline-six. The Audi A7 55 TFSI quattro, another key competitor, comes in slightly lower at 23 MPG combined (20 city/28 highway). Shifting to a V8-powered competitor like the Porsche Panamera GTS, the efficiency drops significantly to 18 MPG combined (16 city/23 highway), clearly showing the benefit of BMW’s powerful yet economical 3.0L inline-six. The 840i Gran Coupe is an efficient choice for a car of its segment, effectively balancing performance with fuel economy, particularly against more powerful M-tuned variants with their lower MPG figures.

Tips to maximize efficiency

To maximize the efficiency of your 840i Gran Coupe, engage Comfort or Eco Pro driving modes. These settings optimize throttle response, transmission shift points, and climate control to prioritize fuel economy, making a noticeable difference in daily driving.

Maintain consistent highway speeds and use the adaptive cruise control. The system maintains optimal distances while minimizing unnecessary acceleration and braking, which are significant fuel detractors.

Regularly check your tire pressures according to BMW’s specifications. Underinflated tires increase rolling resistance, forcing the engine to work harder and directly impacting your MPG figures.

Minimize unnecessary weight in the trunk or cabin. While the 840i Gran Coupe handles added mass well, every extra pound requires more energy to move, particularly in stop-and-go city traffic.

Plan your routes to avoid heavy traffic and excessive idling. The efficient start-stop system helps in urban environments, but minimizing idle time altogether is always the most effective strategy.