The 2021 Mercedes-Benz AMG C63 S Coupe, with its hand-built 4.0L V8, manages just 20 MPG combined. That figure is about as relevant to its target buyer as the thread count of the tires, marginally interesting but ultimately inconsequential. This isn’t a car purchased for its low fuel consumption. Anyone remotely surprised or dismayed by a 20 MPG rating is shopping in the wrong showroom. The C63 S Coupe is for those who prioritize raw, unadulterated performance and a symphonic exhaust note over saving money at the pump.

City and highway performance

The EPA estimates the C63 S Coupe’s city driving fuel economy at 17 MPG. In stop-and-go traffic, expect that figure to dip further, especially with a heavy foot. The V8’s eagerness to unleash its considerable power makes resisting temptation difficult. Out on the open road, the C63 S improves to 26 MPG on the highway. While that number appears respectable, achieving it requires restraint, which is against the car’s very nature. Expect to see closer to the combined figure in real-world mixed driving, as the engine always encourages aggressive acceleration.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2021 Mercedes-Benz AMG C63 S Coupe at $2,900. This figure is based on driving 15,000 miles per year, combining city and highway driving conditions, and using the national average fuel price (for premium gasoline, which is required) at the time of calculation. It’s a benchmark to compare against other vehicles. For an owner who regularly enjoys the C63 S’s performance capabilities, and drives more than the average, that annual cost could easily exceed $4,000.

Real-world expectations

Forget the EPA numbers. Real-world MPG in a C63 S depends entirely on driving style. A lead-footed owner who frequently exploits the engine’s 503 horsepower and 516 lb-ft of torque will inevitably see fuel economy plummet. Conversely, someone who commutes primarily on the highway and exercises extreme self-control might approach the EPA estimates. However, buying a C63 S and driving it conservatively is like purchasing a thoroughbred and using it for pony rides. The pleasure of owning this car is in driving it hard, and that comes with a fuel penalty.

How it compares

The C63 S Coupe exists in a small segment of high-performance coupes. Its closest competitors offer similar, if not marginally better, fuel economy. The BMW M4 Competition, for example, is rated at 16 MPG city and 23 MPG highway. The Audi RS 5 Coupe posts 18 MPG city and 25 MPG highway. These small differences are splitting hairs. The buyer’s decision often comes down to styling, brand loyalty, and driving dynamics, not a 1 or 2 MPG variance. For a broader look, explore all Mercedes Benz fuel economy data. You might also be interested in AMG MPG across all years.

Tips to maximize efficiency

Although saving on fuel is unlikely to be a C63 S owner’s priority, small adjustments can make a difference. Avoid hard acceleration and braking whenever possible. Smooth, progressive inputs are key to conserving fuel, however unnatural they feel in this car.

Use the car’s various driving modes. Selecting “Comfort” mode softens the throttle response and optimizes the transmission for fuel efficiency. This is not the ideal setup for experiencing the car’s performance potential, but it can help in low-speed situations.

Ensure the tires are properly inflated. Underinflated tires increase rolling resistance and negatively impact fuel economy. Refer to the sticker on the driver’s side doorjamb for the recommended tire pressure. Correct inflation pressure also improves vehicle handling.

Minimize idling. A warm engine consumes fuel even when the car is stationary. If you anticipate being stopped for more than a minute or two, turn off the engine. Modern engines are designed to restart quickly and efficiently, so this won’t cause undue wear.

Consider a less aggressive driving style. This is perhaps the most obvious but also the most difficult recommendation to follow. The C63 S begs to be driven hard, but if you are serious about improving fuel economy, resist the urge to constantly explore the upper reaches of the tachometer.