Someone buying a 2018 Mercedes-Benz C300 4matic Convertible likely isn’t prioritizing its 25 MPG combined fuel rating. Buyers want open-air motoring, refined luxury, and confident all-wheel-drive performance in a stylish package. Fuel costs matter, but are less important than the overall experience of owning a premium convertible. This MPG figure is simply part of the cost to enjoy the C300’s unique blend of features.

City and highway performance

The EPA estimates the C300 4matic Convertible gets 22 MPG in the city and 29 MPG on the highway. These figures represent typical driving conditions, but understanding their context is important. City driving, with its stop-and-go traffic and frequent acceleration, will result in lower numbers. A consistent highway speed allows the 2.0L turbocharged engine to settle into its most efficient range, close to 29 MPG. The nine-speed automatic transmission is important here, keeping the engine at optimal RPMs for both power and efficiency. Aggressive driving will always increase fuel consumption.

Annual fuel cost

The EPA estimates the annual fuel cost for driving a 2018 Mercedes-Benz C300 4matic Convertible is $2,300. This is based on driving 15,000 miles per year and assumes the national average fuel price. Because fuel prices change, and individual driving habits vary, consider this only an estimate. Drivers covering more miles or paying higher fuel costs can expect to spend more. This also assumes the use of premium gasoline, which is recommended for a Mercedes Benz.

Real-world expectations

The EPA provides a standard, but real-world MPG often differs. Several factors affect your C300’s fuel efficiency, including driving style, terrain, and even tire pressure. A lead-footed driver in a hilly urban environment will likely see MPG figures below the EPA estimates, while a driver with a light touch on the open highway might surpass them. Regular maintenance, including timely oil changes and air filter replacements, helps fuel economy. The 4matic all-wheel-drive system enhances traction and stability, it adds weight and driveline friction, potentially reducing efficiency compared to a rear-wheel-drive C300.

How it compares

The C300 4matic Convertible is in a small class of luxury convertibles, so direct comparisons need close attention. The BMW 430i xDrive Convertible, a competitor, gets a slightly better 27 MPG combined in EPA testing, with its 2.0-liter turbo-four. Audi’s A5 Cabriolet quattro gets a similar 27 MPG combined. A 2 MPG difference adds up over years of ownership. Potential buyers often compare these vehicles for styling, brand, and driving experience, making fuel costs less important. The Lexus RC 300 AWD is another option, but its fuel economy is lower at 21 MPG combined. For a broader look at the Mercedes family, consider all Mercedes Benz fuel economy data. Information can also be found for the C300 MPG across all years.

Tips to maximize efficiency

Gentle acceleration helps fuel economy. Avoid sudden bursts of speed and instead ease into the throttle. The C300’s turbocharged engine has torque at lower RPMs, supporting relaxed and efficient driving.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, which forces the engine to work harder and uses more fuel. Check your tire pressure regularly and inflate to the levels on the doorjamb sticker.

Reduce weight. Extra cargo adds weight, which affects fuel efficiency. Remove items you don’t need from the trunk and passenger area.

Minimize idling. Idling wastes fuel. If you anticipate a stop longer than a minute, turn off the engine and restart it later.

Use cruise control on the highway. Maintaining a consistent speed can improve fuel economy on long trips. Cruise control helps prevent unintended acceleration and deceleration, improving fuel consumption.