22 MPG combined might initially raise an eyebrow for a modern 2.0L four-cylinder, but for the 2026 Mercedes-Benz AMG SL43, it allows a substantial, luxurious roadster to deliver engaging performance without a profligate thirst. This isn’t merely a base model; it’s an AMG, engineered for spirited driving and open-air enjoyment, yet it still manages to achieve an economy rating many might associate with less premium, less powerful vehicles. The SL43 isn’t for the buyer whose primary concern is hypermiling, but rather for the enthusiast who appreciates a turbocharged engine with electric motor offering both thrills and a practical degree of efficiency for daily use or weekend escapes. Its mission is clear: to blend top-down exhilaration with cutting-edge technology, and its fuel economy figures reflect that deliberate balance.

City and Highway Performance

The 19 MPG in city driving for the SL43 is a respectable figure, especially considering the vehicle’s substantial curb weight and the inherent characteristics of its AMG-tuned 2.0L turbocharged engine, which, let’s not forget, is boosted by a 48-volt mild-hybrid system. Stop-and-go traffic, often the bane of high-performance vehicles, is mitigated somewhat by the integrated starter-generator, allowing for smoother restarts and some degree of electric assist at lower speeds. This isn’t a dedicated hybrid, but the electrification aids in rounding off the rough edges of urban consumption. On the highway, the SL43 truly stretches its legs, delivering a solid 27 MPG. This figure underscores the efficiency gains of modern powertrain technologies when operating under steady-state conditions. The 9-speed automatic transmission plays a key role here, ensuring the engine operates within its most efficient RPM range at cruising speeds, while Mercedes-AMG’s aerodynamic efforts contribute to slicing through the air with minimal drag. The long ninth gear effectively acts as an overdrive, keeping engine revolutions low and fuel consumption in check on extended journeys. It’s a performance car that doesn’t punish the wallet unfairly during a long weekend road trip.

Annual Fuel Cost

The EPA estimates an annual fuel cost of $2,650 for the 2026 Mercedes-Benz AMG SL43. This figure is derived using a standardized calculation: 15,000 miles of driving per year, split evenly between city and highway conditions, and based on national average fuel prices, which for premium fuel can fluctuate. It’s a useful benchmark for comparing vehicles, indicating what the average driver might expect to spend over a year. For the individual considering an AMG SL43, this annual expenditure integrates into the overall cost of ownership of a premium luxury performance convertible. While not insignificant, it’s an expected cost for a vehicle in this class, and one that its target demographic is accustomed to. The $2,650 isn’t a deterrent for someone seeking the unique blend of style, performance, and craftsmanship the SL43 offers; it simply represents a predictable operating expense.

Real-World Expectations

In real-world driving, the 2026 AMG SL43 will likely deliver figures very close to its EPA ratings, provided the driver exercises some restraint. The character of this car, however, often encourages spirited driving, which naturally impacts fuel consumption. The turbocharged 2.0L engine, while efficient for its power output, will consume more fuel when pushed hard, especially when frequently engaging the turbocharger and allowing the engine to rev freely. Owners of the SL43 aren’t buying it to drive like a monk, they are buying it for the thrill of its responsive engine and dynamic chassis. Expect city figures to dip slightly below 19 MPG if you’re frequently enjoying the rapid acceleration and agile handling the SL43 offers. On the highway, maintaining a steady cruise at legal speeds should see figures remaining very close to, or even exceeding, 27 MPG, particularly on flatter terrain. The mild-hybrid system’s electric boost is felt more during city acceleration and stop-start scenarios, subtly improving efficiency where it’s most needed without drawing attention to itself. For all Mercedes Benz fuel economy data, explore the listings available. Ultimately, consistent heavy use of the “Sport+” driving mode will yield a lower MPG, but that’s an understood trade-off for the heightened performance experience.

How It Compares

The 2026 Mercedes-Benz AMG SL43, with its 22 MPG combined, positions itself interestingly against its competitors. A direct rival like the Porsche 911 Carrera (base 3.0L twin-turbo flat-six) typically hovers around 20 MPG combined (18 city/25 highway for the Coupe with PDK), demonstrating that the SL43’s four-cylinder advantage isn’t massive, but it is present. The BMW Z4 M40i, which is perhaps a closer philosophical rival despite its slightly different segment, uses a 3.0L inline-six and achieves a commendable 26 MPG combined (23 city/30 highway). This shows a clear efficiency edge for the BMW, largely attributable to its six-cylinder engine, which, while larger, is engineered for impressive efficiency figures. However, the Z4 lacks the rear seats and the AMG pedigree of the SL43. Another convertible to consider might be the Lexus LC 500 Convertible, with its naturally aspirated 5.0L V8, which manages a much lower 18 MPG combined (15 city/25 highway), reflecting its entirely different powertrain philosophy. The SL43 buyer is not likely cross-shopping the Z4 for its efficiency gains. Instead, they are prioritizing the AMG performance, the unique SL heritage, the luxurious interior, and the specific open-top experience. They understand that for AMG MPG across all years, performance often comes with a financial obligation at the pump, and the SL43 strikes a balance for them without sacrificing the core AMG experience.

Tips to Maximize Efficiency

Maintaining proper tire pressure is one of the easiest and most effective ways to ensure your SL43 performs optimally, both in terms of handling and fuel economy. Consult your owner’s manual or the sticker inside the driver’s door jamb for the recommended pressures and check them regularly, preferably when the tires are cold.

While the AMG SL43 encourages spirited driving, adopting a smoother driving style when conditions allow can significantly impact your MPG. Gradual acceleration, anticipating traffic to avoid hard braking, and maintaining a consistent speed on the highway reduce strain on the engine and transmission, leading to better fuel efficiency.

Use the SL43’s selectable drive modes effectively. The “Comfort” or “Slippery” modes will typically prioritize efficiency by softening throttle response, allowing for earlier upshifts, and reducing the engine’s propensity to hold higher RPMs, making them ideal for daily commuting or relaxed highway cruising.

Avoid carrying unnecessary weight in the trunk. While the SL43 isn’t a cargo hauler, even small amounts of extra weight accumulate, requiring more energy from the engine to move the vehicle and slightly reducing its overall efficiency.

Regular maintenance is crucial for not only the longevity of your AMG SL43 but also its fuel economy. Adhering to Mercedes-Benz’s recommended service schedule ensures the engine, transmission, and all related systems are operating at peak efficiency, preventing minor issues from impacting fuel consumption.