24 MPG combined makes the 2025 Mercedes-Benz S500 4matic 3.0L 6-cyl efficient within the full-size luxury sedan segment. This figure balances comfort and performance with a sensible approach to fuel consumption. This isn’t a vehicle purchased out of strict economic necessity; it’s a statement of status, technology, and refined engineering. Buyers of the S500 appreciate its effortless power delivery, its quiet cabin, and its unparalleled ride quality. They demand excellence in every metric, and while fuel economy isn’t their primary driver, an intelligent use of resources is always valued. The 24 MPG combined rating is due to Mercedes-Benz’s advancements in mild-hybrid technology and powertrain calibration, delivering a flagship sedan that doesn’t feel unduly penalized at the pump.

City and highway performance

Breaking down the combined figure, the 2025 S500 4matic achieves 21 MPG in city driving and a remarkable 31 MPG on the highway. The city MPG is particularly impressive for a vehicle of this size and heft, a direct result of the integrated starter-generator (ISG) mild-hybrid system. This EQ Boost system aids acceleration with a temporary electric assist and, more importantly, allows for smooth engine stop/start functionality and coasting, significantly reducing fuel consumption during stop-and-go traffic. On the open road, the 3.0L inline-six, paired with its smooth 9-speed automatic transmission, settles into an efficient cruise. The transmission’s wide gear ratios ensure the engine operates at optimal RPMs, silently consuming highway miles with a surprising parsimony for a luxury cruiser. The smooth transitions of the 9G-TRONIC transmission are instrumental in achieving these figures, ensuring power is always delivered efficiently without harsh shifts that can waste energy.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,400 for the 2025 Mercedes-Benz S500 4matic 3.0L 6-cyl. This figure is calculated based on a national average of 15,000 miles driven per year, split between city and highway driving, and using national average fuel prices for premium gasoline. For the S-Class buyer, this $2,400 annual outlay is a relatively minor line item in the overall cost of vehicle ownership. It represents a predictable expense for a car that delivers such an elevated driving experience. Those who purchase an S500 typically prioritize their time and comfort, viewing this fuel expense as a perfectly acceptable cost for the privilege of driving one of the world’s finest automobiles. It’s a pragmatic number for a vehicle that’s anything but.

Real-world expectations

In real-world driving, the 2025 S500 4matic often lives up to its EPA estimates, particularly for drivers who frequently engage in highway cruising. The mild-hybrid system truly shines in mixed driving conditions, making a noticeable difference in stop-and-go scenarios. Aggressive driving habits, however, will naturally see those numbers dip. The 3.0L inline-six, with its 429 horsepower and 384 lb-ft of torque, can certainly be provoked into using more fuel if the driver constantly exploits its impressive performance capabilities. However, the S-Class is designed for refined, effortless progress, not hot-rod antics. When driven as intended, smoothly, confidently, and with an appreciation for its engineering, drivers can expect to routinely achieve figures close to the EPA’s 24 MPG combined rating, and even exceed the 31 MPG highway number on long, steady cruises. For more information on this specific model, you can review S500 MPG across all years.

How it compares

The 2025 Mercedes-Benz S500 4matic sits competitively among its peers when considering fuel economy. Its closest rival, the BMW 740i xDrive, also powered by a 3.0L inline-six mild-hybrid, achieves an identical 24 MPG combined (22 city / 31 highway). This parity highlights the advanced state of six-cylinder mild-hybrid powertrains in the luxury segment. The slightly more powerful Audi A8 55 TFSI quattro, with its 3.0L turbo V6, generally returns around 22-23 MPG combined. If one were to step up to a V8-powered variant in this class, such as the S580 e 4MATIC with its plug-in hybrid system (which drastically alters its EPA ratings to 58 MPGe combined) or the pure gasoline S580 4MATIC (aiming for around 19 MPG combined), the S500’s efficiency advantage becomes even more pronounced. The S500 offers a balance, providing ample power suited for its luxury mission without the significant fuel consumption penalty of stepping up to larger engines, or the complexity of a plug-in lifestyle. For a deeper dive into Mercedes-Benz vehicles, check out all Mercedes Benz fuel economy data.

Tips to maximize efficiency

To get the most out of your S500 4matic’s fuel economy, use the EQ Boost system. Allow the engine start/stop function to operate freely, it’s designed to be smooth and dramatically reduces fuel consumption during idling in traffic.

Engage the ECO driving mode when conditions permit. This mode optimizes throttle response, transmission shift points, and climate control operation to prioritize fuel efficiency without sacrificing the S-Class’s inherent refinement.

Maintain consistent highway speeds. The S500’s ninth gear is incredibly efficient, and avoiding frequent acceleration and deceleration on the open road will keep the engine operating in its most economical range.

Regular maintenance is crucial. Ensure your tires are properly inflated to the manufacturer’s recommended pressures and adhere to the scheduled service intervals to keep the engine and transmission operating at peak efficiency.

Anticipate traffic flow. Smooth, gradual braking and acceleration not only contribute to a more comfortable ride, which is the S-Class’s hallmark, but also allow the mild-hybrid system to recuperate more energy and reduce fuel usage.