25 MPG combined, a figure often associated with compact crossovers or even some full-size sedans, is an impressive achievement for the 2025 Mercedes-Benz E450 4Matic. This isn’t a four-cylinder economy car; it’s an all-wheel-drive luxury executive sedan weighing over two tons, powered by an inline-six engine with a mild-hybrid system. The E450’s mission is not to win drag races at every stoplight, but to transport its occupants in quiet comfort and effortless power, often across significant distances. For the individual who values refinement, quality, and a deeply satisfying driving experience above all else, this 25 MPG shows intelligent engineering, ensuring that their premium ownership experience isn’t unduly penalized at the pump.

City and highway performance

The E450 4Matic’s 22 MPG in city driving conditions reflects the efficiency benefits of its 3.0L inline 6-cylinder engine, augmented by Mercedes-Benz’s 48-volt mild-hybrid EQ Boost system. In stop-and-go traffic, the electric motor can provide a brief, silent assist during acceleration, smoothing out power delivery and reducing the workload on the gasoline engine. The smooth start/stop function, enabled by the integrated starter-generator, operates with a level of precision rarely found outside of Mercedes-Benz, restarting the engine almost imperceptibly as soon as the driver lifts off the brake. On the open road, the E450 truly shines, delivering a strong 31 MPG highway. This number is a direct result of several factors: the nine-speed automatic transmission’s expansive gear ratios, which allow the engine to cruise at remarkably low RPMs, the aerodynamic shape inherent in the E-Class sedan’s design, and the inherent efficiency of the modern inline-six engine when operating under steady-state conditions. Mercedes-Benz engineers have balanced performance with efficiency, ensuring that the highway cruise is not only comfortable but also commendably economical for a car of this caliber.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,300 for the 2025 Mercedes-Benz E450 4Matic. This figure is based on an assumed 15,000 miles of driving per year, split evenly between city and highway conditions (45% city, 55% highway), and using national average fuel prices, which for premium gasoline are typically higher than regular unleaded. For the E450 owner, this $2,300 expenditure is not an exorbitant sum, particularly when viewed in the context of the vehicle’s purchase price, insurance, and maintenance. Those who choose the E450 are typically financially established, often valuing their time and comfort above marginal fuel savings. For them, paying a modest premium for fuel to enjoy the effortless power, peerless refinement, and advanced technology of a Mercedes-Benz is an entirely sensible trade-off. It’s an anticipated cost of ownership, a small fraction of the overall investment in a truly superior driving machine.

Real-world expectations

In the real world, the E450 4Matic will likely meet or even slightly exceed its combined 25 MPG rating for most drivers. Mercedes-Benz powertrains, especially those with mild-hybrid assistance, are often optimized for efficient cruising and moderate acceleration, which aligns with how most luxury sedan owners operate their vehicles. Drivers who consistently engage in aggressive acceleration from every stoplight or spend the majority of their time in heavy, bumper-to-bumper city congestion might see numbers closer to the 22 MPG city rating. Conversely, those whose commutes involve extended stretches of open highway and who practice a smooth, anticipatory driving style will frequently observe figures above the 31 MPG highway rating. The car’s intrinsic refinement encourages a calmer driving demeanor, which naturally contributes to better fuel economy. The intelligent cruise control systems and well-calibrated automatic transmission actively work to optimize efficiency, subtly guiding the driver toward more economical habits without sacrificing the driving experience. Owners of all Mercedes Benz fuel economy data benefit from this integration.

How it compares

The 2025 Mercedes-Benz E450 4Matic enters a competitive segment, but its combination of powertrain, luxury, and efficiency holds its own remarkably well. Consider the Audi A6 55 TFSI quattro, which also features a 3.0L turbocharged V6 and all-wheel drive. That vehicle typically achieves 24 MPG combined (21 city / 30 highway), putting it just slightly behind the E450 despite having similar performance metrics. The BMW 540i xDrive, another inline-six rival (3.0L turbo), often lands around 26 MPG combined (23 city / 31 highway), marginally exceeding the E450. However, the differences in driving dynamics and interior philosophy are significant. The BMW prioritizes a slightly sportier edge, while the E450 offers comfort and technological features. For the buyer focused on fuel economy within the premium mid-size sedan segment, these marginal differences are often secondary to brand loyalty and the overall ownership experience. Volvo’s S90 B6 AWD, with its 2.0L turbo- and supercharged engine, achieves 25 MPG combined as well (23 city / 31 highway) but offers a distinctly different Scandinavian aesthetic and less power than the E450’s inline-six. Each of these vehicles caters to a specific luxury buyer, and the E450 positions itself as the choice for those prioritizing quiet comfort, effortless power, and elegant design, with fuel economy that is entirely appropriate for its class. For a broader look at this model, you can review E450 MPG across all years.

Tips to maximize efficiency

Maintaining proper tire inflation is important for any vehicle, but particularly for a luxury sedan like the E450. Underinflated tires increase rolling resistance, forcing the engine to work harder and consistently degrading fuel economy. Check your tire pressures monthly, adhering to the manufacturer’s recommended cold inflation pressures found on the driver’s side door jamb placard.

Effective use of the E450’s EQ Boost system involves smooth, gradual acceleration. Avoid sudden, aggressive inputs on the accelerator pedal. Instead, allow the electric motor to assist the inline-six, minimizing the gasoline engine’s initial fuel consumption and optimizing the hand-off between electric assist and combustion power.

Use the Eco driving mode, which specifically tailors the transmission shift points, throttle response, and climate control operation for optimal fuel efficiency. While Sport mode might be more engaging, Eco mode is designed to make the most of every drop of fuel without overtly sacrificing the E-Class’s driving characteristics.

Anticipate traffic conditions well in advance to minimize unnecessary braking and acceleration. Smooth, consistent driving by maintaining a safe following distance and looking far down the road allows the E450’s mild-hybrid system to more effectively perform regenerative braking, recovering energy that would otherwise be lost and subtly recharging the 48-volt battery for future assistance.

Keep up with the manufacturer’s recommended maintenance schedule. A well-tuned engine, clean air filters, and fresh spark plugs all contribute to optimal combustion and performance. Neglecting routine service can gradually decrease efficiency, a subtle but persistent drain on your fuel economy over time.