19 MPG combined is what you get with the 2018 Mercedes-Benz AMG C63 S Convertible. It’s a strong, beautifully crafted machine designed to deliver thrills above all else. This isn’t a car bought for its low fuel consumption; it’s purchased by those who prioritize the sound of a hand-built V8, the rush of open-air driving, and the prestige of the AMG badge. Fuel economy is, for this buyer, a secondary concern, a compromise accepted for the immense performance.

City and highway performance

The EPA estimates the C63 S Convertible will get 17 MPG in the city and 22 MPG on the highway. While these numbers might seem underwhelming, remember the engine’s character. The 4.0L twin-turbocharged V8 is a powerhouse, delivering immense torque at low RPMs. This contributes to the car’s responsiveness in city driving, but also means you are always a press of the accelerator away from serious power. On the highway, getting 22 MPG requires restraint. High-speed cruising will likely see numbers drop slightly, as the temptation to exploit the engine’s capabilities is often irresistible. The seven-speed automatic transmission, while smooth and responsive, is geared more for performance than maximizing fuel efficiency. It will hold gears longer than a comparable transmission in a less performance-focused vehicle.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Mercedes-Benz AMG C63 S Convertible at $3,050. This figure is calculated based on driving 15,000 miles per year, with a mix of city and highway driving, and using the national average fuel price for premium gasoline, which this car demands. Understand that this $3,050 figure is an estimate. Your actual fuel costs can vary significantly based on your driving habits, the type of driving you do (city vs. highway), and fluctuations in local fuel prices. Aggressive driving will push that cost higher, while more conservative driving might lower it slightly. Owning a high-performance vehicle like the C63 S Convertible inherently means accepting a higher fuel bill.

Real-world expectations

Don’t focus on the window sticker. Real-world fuel economy for the C63 S Convertible is almost always going to be lower than the EPA estimates, especially if you frequently push the car’s performance. Drivers should realistically expect to see combined fuel economy hovering around 15-18 MPG, with city driving possibly dipping into the low teens. The sound of the V8 encouraging you to drive harder, combined with the car’s impressive acceleration, makes it difficult to drive with fuel efficiency in mind. If you want to squeeze every last mile out of a gallon, this is the wrong car. This is a weekend thrill ride, a statement piece. For the target demographic, the cost of fuel is likely a far lesser constraint than the monthly payments or insurance premiums.

How it compares

Compared to other high-performance convertibles, the C63 S falls roughly in the middle of the pack in terms of fuel economy. The BMW M4 Convertible, for instance, gets an EPA-rated 19 MPG combined with its inline-six engine, a figure that is theoretically equal to the C63 S, but often sees better real-world efficiency due to its engine’s responsive, but less peaky, power delivery. The Audi RS5 Convertible, powered by a twin-turbo V6, also offers similar performance but often boasts slightly better fuel economy, hovering around 20 MPG combined. A V8-powered Ford Mustang GT Convertible, while significantly less expensive, offers similar power levels, but fuel economy suffers, getting about 18MPG combined. These comparisons matter to the potential C63 S buyer because they highlight the trade-offs. Are they willing to accept slightly lower MPG in exchange for the unique sound and character of the AMG V8, or would they prefer a more efficient, but perhaps less emotionally engaging, alternative?

Tips to maximize efficiency

Smooth throttle inputs are important. Avoid sudden acceleration and heavy braking, as these actions dramatically increase fuel consumption. The C63 S is responsive, and gentle pressure on the accelerator delivers ample power. Treat the throttle delicately, especially in city driving.

Use the car’s drive modes. The “Comfort” mode will soften throttle response and encourage earlier upshifts, promoting better fuel economy. While it might not be the most exciting way to drive, it’s a sensible option for daily commuting.

Regular maintenance is essential. Ensure the engine is properly tuned and that the tires are correctly inflated. A well-maintained engine operates more efficiently, and properly inflated tires reduce rolling resistance. Both contribute to improved fuel economy. Check all Mercedes Benz fuel economy data.

Avoid extended idling. If you’re stopped for more than a minute, turn off the engine. Idling consumes fuel without providing any forward motion. Stop-start systems in many modern vehicles address this issue, but manually shutting off the engine can still make a difference.

Plan your routes strategically. Minimize stop-and-go traffic and choose routes that allow for consistent speeds. Highway driving generally yields better fuel economy than city driving, so opt for the highway when possible. Note that AMG MPG across all years are generally lower than Mercedes Benz cars.