The 2015 Mercedes-Benz CLS550 gets 20 MPG combined. It’s a number to consider, especially now that fuel efficiency is always improving. But this number has to be considered while keeping in mind what the CLS550 is: a stylish, powerful, and luxurious four-door coupe. This car isn’t for someone obsessed with getting the best mileage; it’s for the driver who appreciates strong V8 performance in a sleek, attention-grabbing package, and who is willing to pay more at the pump for that experience.

City and highway performance

The EPA estimates the CLS550’s fuel economy at 18 MPG in the city and 26 MPG on the highway. These numbers are based on the demands on the 4.7-liter twin-turbocharged V8 engine in different driving conditions. City driving, with its stop-and-go traffic, frequent acceleration, and idling, uses more gas. The CLS550’s weight also leads to lower city MPG. Highway driving lets the engine run more efficiently, using the nine-speed automatic transmission to keep the engine at its best. While 26 MPG isn’t record-setting, it’s respectable for a car with this much performance and luxury on the road.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Mercedes-Benz CLS550 at $2,900. This number is based on driving 15,000 miles per year, with a percentage of those miles in the city versus the highway, using national average fuel prices when the EPA calculated. It’s a good number to know, providing a standard for comparing fuel costs between vehicles. Your actual fuel costs will vary depending on your driving, local fuel prices, and the type of fuel. Using premium fuel, which is recommended for the CLS550, will likely increase your annual fuel expenses above the EPA’s $2,900 estimate.

Real-world expectations

The EPA provides fuel economy estimates, but real-world MPG can change. Aggressive driving, short trips, and carrying extra weight will hurt fuel economy. Gentle acceleration, consistent highway speeds, and correct tire inflation can help you get closer to the EPA estimates, or even a little better. The CLS550 encourages fast driving, but controlling yourself is important for getting the best mileage. Watching your fuel consumption through the car’s trip computer can give you information about your driving and its effect on MPG. Looking at CLS550 MPG across all years shows a consistent range, suggesting real world performance closely matches the EPA figures reported.

How it compares

The CLS550’s fuel economy places it in the luxury performance market. The 2015 Audi S7, a stylish four-door coupe with a turbocharged V8 engine, gets 21 MPG combined, which is slightly better. A BMW 650i Gran Coupe from the same year, also with a V8, gets similar numbers to the CLS550, around 19 MPG combined. The Porsche Panamera, particularly in higher-performance trims, often has similar or lower fuel economy figures based on the engine. These comparisons matter because CLS550 buyers often compare these vehicles, looking at performance, luxury, style, and fuel costs. Knowing how these options compare allows for a more informed decision, even if fuel economy isn’t the main thing. For a broader comparison, browse all Mercedes Benz fuel economy data.

Tips to maximize efficiency

Gentle acceleration is important. The CLS550’s twin-turbo V8 makes power quickly, making it tempting to accelerate fast. But easing onto the gas pedal, especially when starting, uses less fuel. Anticipating traffic and keeping a steady speed will also help you save gas.

Tire pressure matters. Make sure your tires are inflated to the recommended pressure on the driver’s side doorjamb. Underinflated tires increase rolling resistance, making the engine work harder and using more fuel. Checking tire pressure often is a simple way to improve MPG.

Avoid idling. Modern engines are more efficient when running than when idling. Avoid unnecessary idling, especially in stop-and-go traffic. If you’re stopped for more than a minute, turn off the engine. The CLS550’s quick restart system makes this easy.

Use cruise control on the highway. Cruise control helps keep a consistent speed, stopping changes in the gas pedal that can hurt fuel economy. This is helpful on long highway drives where speed changes are common.

Regular maintenance is critical. A well-maintained engine runs more efficiently. Follow the manufacturer’s maintenance schedule, including oil changes, air filter replacements, and spark plug replacements. These small things can noticeably improve fuel economy.