16 MPG combined is what buyers can expect from the 2023 Mercedes-Benz AMG SL55 4matic Plus. It’s not a Prius, and makes no claim to be. This is a high-performance roadster built to deliver exhilarating driving experiences, prioritizing power and prestige over fuel efficiency. Owners are paying for a statement, an experience, and the privilege of piloting a hand-built AMG engine; fuel costs are a secondary concern.

City and highway performance

The AMG SL55’s EPA ratings are 13 MPG in the city and 21 MPG on the highway. The city figure shows the engine’s thirst during stop-and-go traffic, made worse by its large displacement and turbocharging. The highway number, while better, still shows that sustained high-speed cruising in a performance car requires significant fuel consumption. The 9-speed automatic optimizes efficiency, but its primary function is the engine’s power delivery, keeping it in the optimal range for immediate response.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2023 AMG SL55 is $3,600. This is based on driving 15,000 miles per year, with a mix of city and highway driving, and using the national average fuel price. Remember that premium fuel is required for the AMG SL55, further increasing your real-world fuel expenses relative to the EPA’s estimate.

Real-world expectations

The EPA ratings provide a standardized benchmark, but your personal driving style and conditions greatly affect your actual fuel consumption. Enthusiastic acceleration, frequent short trips, and prolonged idling will all lower your MPG below the official figures. However, smooth, consistent highway driving might get you closer to, or even slightly above, the 21 MPG highway rating. Consider the EPA number a baseline, not a guarantee.

How it compares

Its direct competitors don’t get much better gas mileage, solidifying the SL55’s place in a segment unconcerned with less gas. The Porsche 911 Carrera S Cabriolet, while slightly better, only manages around 18 MPG combined. A BMW M850i Convertible achieves approximately 20 MPG combined, a minor improvement but for a car with a different character. Buyers likely cross-shopping these vehicles understand and accept the trade-off between performance and economy, and these small MPG differences are unlikely to be deciding factors. Comparing it to something like, maybe even within the Mercedes Benz fuel economy data stable, an E-Class Cabriolet with a smaller engine, which can get 25 MPG combined, is relevant only in that it highlights the buyer’s intentional choice to prioritize experience over efficiency. You can also find the detailed AMG MPG across all years.

Tips to maximize efficiency

Fuel economy isn’t the main concern for AMG SL55 owners, but some small changes can lead to savings. Avoid aggressive acceleration and hard braking. The AMG’s powerful engine responds readily to even moderate throttle inputs, so smooth and progressive acceleration uses less fuel.

Maintain proper tire inflation. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the recommended levels. You can find the correct pressures on a sticker inside the driver’s side door jamb.

Minimize idling. Idling consumes fuel, and covers no distance. Avoid prolonged idling, especially in cold weather, which greatly reduces fuel economy and increases emissions. Turn off the engine if you anticipate waiting for more than a minute.

Use the car’s driving modes carefully. The AMG SL55 offers driving modes that adjust engine response, transmission mapping, and suspension settings. Choose the “Comfort” or “Eco” mode for everyday driving to prioritize fuel efficiency over outright performance. These modes typically soften throttle response and encourage earlier upshifts, reducing fuel consumption.