22 MPG combined is likely not the primary reason someone buys a 2020 Mercedes-Benz S450 3.0L 6-cyl. This car is geared towards executives, celebrities, and individuals who value quiet comfort, state-of-the-art technology, and a commanding appearance most of all. Fuel economy is a secondary consideration, but knowing its efficiency remains relevant even for those accustomed to luxury vehicles.

City and highway performance

Achieving 19 MPG in the city with a large, powerful sedan is acceptable. The S450’s 3.0L turbocharged inline-six engine, along with a smooth-shifting 9-speed automatic transmission, provides plenty of power for confident acceleration. However, stop-and-go traffic will impact fuel economy. On the open highway, the S450 performs better, reaching 28 MPG. This indicates the car’s relaxed behavior at cruising speed, where the engine uses less fuel while providing a remarkably quiet and comfortable ride.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2020 Mercedes-Benz S450 at $2,650. This calculation is based on driving 15,000 miles per year and using national average fuel prices. For drivers who spend time in congested cities, or who accelerate quickly, this figure could increase. However, these buyers shouldn’t find the $2,650 figure to be an obstacle. Those who primarily use the S450 for long highway trips may find their actual fuel costs are lower.

Real-world expectations

MPG expectations for the S450 should be moderate. While the EPA ratings provide a general idea, real-world fuel economy will change based on driving style, traffic, and even weather. Strong acceleration, frequent hard braking, and long periods of idling will all reduce fuel consumption. The S450’s weight and focus on performance mean that achieving the advertised MPG figures requires an effort to drive efficiently. However, even in less ideal situations, drivers should see figures reasonably close to the EPA estimates, thanks to the engine’s advanced technology and well-calibrated transmission.

How it compares

The 2020 Mercedes-Benz S450’s fuel economy is in line with other luxury sedans in its class. The BMW 740i, with its similar 3.0L turbocharged inline-six, achieves similar combined MPG. The Audi A8 shows similar numbers, as well. Of course, choosing a V8-powered S560 will likely result in combined MPG in the mid-teens. For buyers comparing these sedans, overall comfort, technology, and brand reputation tend to matter more than minor differences in fuel efficiency. See all Mercedes Benz fuel economy data to compare to other models. You can also view S450 MPG across all years.

Tips to maximize efficiency

The S450’s driving mode selector allows you to prioritize efficiency through “Eco” mode. This setting reduces throttle response, encourages earlier upshifts, and manages the engine for less fuel consumption. Use it when possible, especially during commutes or on long highway stretches.

Consistent maintenance is important for good fuel economy. Make sure that your S450 receives regular oil changes, air filter replacements, and tire pressure checks. Properly inflated tires reduce rolling resistance, and a clean air filter ensures the engine gets enough air to run efficiently.

Minimize idling whenever possible. The S450 consumes fuel even when stationary. Avoid unnecessary idling in traffic or while waiting. The car’s start/stop system will help in these situations by shutting off the engine automatically at stoplights to save fuel.

Avoid aggressive acceleration and braking. The S450’s strong engine can be tempting, but frequent bursts of acceleration and hard braking reduce fuel efficiency. Drive smoothly, predicting traffic flow and maintaining a consistent speed.