21 MPG combined isn’t a fuel economy figure most premium sedans would advertise. The 2017 Mercedes-Benz S550 is different. It’s a flagship, a statement of engineering, luxury, and performance, where efficiency is less important than power and comfort. Buyers of this vehicle prioritize a peerless driving experience, and they are willing to pay more at the pump.

City and highway performance

The S550’s EPA ratings are 18 MPG in the city and 26 MPG on the highway. The city number reflects the challenge of moving a large sedan through stop-and-go traffic, where idling and acceleration use more fuel. The highway figure shows the effectiveness of the nine-speed automatic transmission, allowing the engine to cruise at lower RPMs, which maximizes efficiency. This split performance might appeal to those who primarily use the S550 for longer commutes or weekend trips, offsetting city driving with more efficient highway miles.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2017 Mercedes-Benz S550 is $2,750. This is based on driving 15,000 miles per year, with 55% in the city and 45% on the highway, and using the national average fuel price. This is an important number for potential buyers, representing a recurring expense. Actual fuel costs can vary depending on individual driving and fuel prices. You can browse S550 MPG across all years to see if later versions offer improvement.

Real-world expectations

EPA estimates provide a baseline, but real-world fuel economy for the S550 often differs. Aggressive driving, especially frequent acceleration to access the twin-turbo V8’s power, will reduce fuel efficiency. A relaxed driving style with gentle acceleration and consistent speeds can achieve results closer to the EPA’s estimates, or even better, especially on long highway trips. Ambient temperature, tire pressure, and the use of air conditioning also affect efficiency.

How it compares

The 2017 S550’s fuel economy is typical for its class. The BMW 750i xDrive from the same year, with its 4.4L V8, offers a similar 17 MPG city and 25 MPG highway. The Audi A8 4.0T achieves around 19 MPG city and 29 MPG highway, even with a smaller engine. The Lexus LS 460 gets 16 MPG city and 24 MPG highway. These slight variations are less important to buyers than driving feel and interior comfort, but a buyer will still consider the long-term costs.

Tips to maximize efficiency

Use the S550’s “Comfort” driving mode, which optimizes the engine and transmission for smoother acceleration and earlier gear changes to save fuel. Avoid aggressive acceleration and hard braking, because these consume more fuel. The S550’s powerful engine accelerates well without needing to push it hard.

Keep your tires inflated to the recommended pressure, since low tires increase rolling resistance, reducing fuel economy. Regular tire pressure checks are also important, especially when temperatures fluctuate, decreasing pressure during colder weather.

Minimize idling. Idling uses fuel without traveling any distance. Turn off the engine when waiting for extended periods, such as at long traffic lights.

Use cruise control on the highway to maintain a consistent speed, improving fuel efficiency. Avoid frequent speed changes and sudden acceleration, which consume more fuel. Cruise control also helps prevent speeding, which reduces fuel economy.

Consider using premium fuel as recommended by Mercedes-Benz. Premium fuel optimizes engine performance and prevents knocking, which can indirectly impact fuel efficiency. See all Mercedes Benz fuel economy data here.