The official EPA estimate for the 2015 Mercedes-Benz CLS400 4matic is 22 MPG combined. This car isn’t a commuter; it’s a statement about performance, luxury, and style. Fuel economy is a consideration, but not the main reason someone buys a CLS400. Buyers want the smooth power of the turbocharged 3.0L V6, the all-weather confidence of 4matic all-wheel drive, and the Mercedes-Benz look on a sculpted four-door coupe.

City and highway performance

The EPA numbers are 19 MPG in the city and 26 MPG on the highway. The city MPG shows the engine’s ability to accelerate quickly, helped by the 4matic system’s weight. On the open road, the 26 MPG highway figure shows the CLS400 can cruise comfortably and efficiently, thanks to the smooth seven-speed automatic transmission. Keep in mind that “your mileage may vary”, since driving style and traffic make a big difference. Someone who often uses the engine’s 329 horsepower will see lower MPG.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Mercedes-Benz CLS400 4matic at $2,650. This is based on driving 15,000 miles per year, the EPA’s combined MPG rating of 22, and the national average fuel price for premium unleaded gasoline. The expense is useful when comparing running costs against other vehicles, but individual expenses change based on local fuel prices and driving habits. It’s not the most fuel-efficient car, but the expense is manageable for those who buy this stylish four-door coupe.

Real-world expectations

Most CLS400 owners report MPG numbers that differ from the EPA’s 22 MPG combined rating. Drivers who enjoy a spirited driving experience and often drive in stop-and-go city traffic might see numbers closer to 17-19 MPG. However, drivers who focus on smooth highway cruising and drive efficiently might see improvements, potentially reaching 28-30 MPG on longer trips. Factors such as tire inflation, vehicle maintenance, and air conditioning can all affect overall fuel economy.

How it compares

The CLS400’s fuel economy puts it in a specific group of competitors. The BMW 640i Gran Coupe is a direct competitor known for its performance and luxury. The rear-wheel-drive 640i Gran Coupe has an EPA-estimated 22 MPG combined, the same as the CLS400. Choosing BMW’s xDrive all-wheel-drive system usually lowers MPG a small amount. The Audi A7 3.0T quattro also has an EPA combined rating around 22-23 MPG. Buyers in this category compare vehicles with similar performance and style. They are aware of the tradeoff with fuel economy, and are willing to accept certain consumption for the driving experience a vehicle like the CLS400 provides. You can find all Mercedes Benz fuel economy data on our site, as well as CLS400 MPG across all years.

Tips to maximize efficiency

The CLS400’s turbocharged engine works best with smooth acceleration. Avoid quickly pressing the throttle and speeding up suddenly, especially in the city. Watch the traffic and keep a consistent speed when you can, and you can greatly improve fuel economy.

Your tires should be inflated to the recommended pressure. Low tire pressure increases rolling resistance, forcing the engine to work harder and consuming more fuel. Check your tire pressure regularly and adjust them as needed, using the specifications listed on the driver’s side doorjamb. Correctly inflated tires also improve handling and make tires last longer.

Remove extra weight from the trunk or cabin. Every extra pound puts strain on the engine, reducing fuel efficiency. Though the CLS400 is comfortable for long trips, avoid using as a storage container for items you don’t need. The lighter the car, the more efficient it is.

Follow the Mercedes-Benz recommended service intervals for regular maintenance, including oil changes, air filter replacements, and spark plug checks. A well-maintained engine runs more efficiently and saves fuel. Ignoring maintenance can decrease performance and increase fuel consumption.