The 16 MPG combined rating for the 2025 Mercedes-Benz AMG SL63 4Matic+ is not a statistic that typically factors into the purchase decision of an individual who buys this vehicle. This isn’t a family hauler, a commuter car, or an SUV designed to maximize range. It is a supremely powerful, luxurious, and engaging grand tourer, a machine built to devour continents with effortless speed and exquisite comfort. The combined MPG reflects the reality of a twin-turbocharged 4.0-liter V8 engine pushing nearly 4,300 pounds with all-wheel drive, a power plant designed for immediate, relentless acceleration, not frugal sips of premium unleaded. Buyers of the SL63 understand and accept this. Indeed, for many, the very existence of such a powerful engine, with its accompanying thirst, is part of the allure. This is performance you feel, hear, and occasionally, refuel.

City and Highway Performance

The EPA rates the AMG SL63 at 13 MPG in the city and 21 MPG on the highway. In city driving, the 4.0L V8, even when paired with the 9-speed automatic, frequently operates under conditions that demand more fuel. Stop-and-go traffic, constant acceleration from lights, and the occasional burst of speed to seize a gap are all part of the urban experience, and the engine, ever eager, obliges with a hearty consumption. The 4Matic+ all-wheel drive system, while offering incredible grip and confidence, also contributes to a slight increase in parasitic losses, albeit imperceptible to the driver. On the open road, the highway figure of 21 MPG becomes more attainable. At steady cruising speeds, the 9-speed transmission allows the engine to settle into its long-legged stride at lower RPMs, where the twin-turbo V8 becomes surprisingly efficient for its output. Engage the various AMG Dynamic Select modes, particularly “Comfort,” and the throttle mapping smooths out, the transmission shifts early, and the car settles into a rhythm more conducive to maximizing that highway figure. However, the temptation to dip into its 577 horsepower for an effortless overtake or a thrilling on-ramp acceleration surge is ever-present, and those moments, while exhilarating, will quickly pull the real-world highway economy closer to the combined average. For data on other AMG models, explore AMG MPG across all years.

Annual Fuel Cost

The EPA estimates an annual fuel cost of $3,600 for the 2025 Mercedes-Benz AMG SL63 4Matic+. This figure is derived assuming 15,000 miles of driving per year, split between 45% highway and 55% city driving, and using national average fuel prices for premium unleaded. For someone considering an SL63, this $3,600 annual expenditure is a rounding error in the context of the vehicle’s purchase price and overall running costs. The buyer of an AMG SL63 is making a statement about performance, luxury, and engineering prowess, and the cost of fuel is simply a recurring operational expense, not a deterrent. Owners are more likely to be concerned with finding the right octane level to ensure optimal engine performance and maintain the vehicle’s warranty, rather than meticulously tracking their monthly fuel bills. The experience of driving an SL63, with its blistering acceleration, precise handling, and opulent interior, far outweighs any concern over what amounts to roughly $300 a month in fuel for the typical driver.

Real-world expectations

In the real world, owners of the AMG SL63 often report fuel economy figures that align closely with the EPA’s estimates, sometimes slightly lower if their driving habits lean heavily on the “Sport+” or “Race” modes. This is a vehicle that actively encourages spirited driving, the glorious exhaust note, the lightning-quick shifts, and the immense power are all designed to be used. Driving the SL63 at its full potential, even intermittently, drastically impacts fuel consumption. Short trips, heavy traffic, and frequent wide-open throttle applications will see the MPG hover closer to the city rating, or even below it. On extended road trips, however, where highways are open and speeds are consistent, hitting the 21 MPG highway number is entirely feasible, especially with an eye on conservative throttle input. The SL63 is about choices: immense power on demand, or a more restrained touring pace. Both are possible, and both dictate fuel economy.

How it compares

When pitted against its direct competitors, the 2025 Mercedes-Benz AMG SL63 occupies a similar fuel economy landscape. Take the Porsche 911 Turbo S Cabriolet, for instance, which typically registers around 19 MPG combined (15 city/20 highway in its previous iteration). While slightly better on paper, the difference is negligible in real-world cost and practicality for buyers in this segment. The Aston Martin Vantage Roadster, with its own AMG-derived 4.0L twin-turbo V8, also sits in a similar range, often around 18 MPG combined (15 city/22 highway). Even a more track-focused machine like the McLaren 720S Spider returns around 18 MPG combined. These vehicles are all part of a performance-oriented ecosystem where outright power and handling take precedence over efficiency. None of these machines are purchased with a primary focus on fuel economy, they are chosen for their engine’s character, their brand cachet, their dynamic capabilities, and their luxurious appointments. The SL63 owner is likely cross-shopping within this very specific niche, understanding that their choice is about an experience, not an expense report dictated by the gas pump. For all Mercedes Benz fuel economy data, check out our Mercedes Benz articles.

Tips to maximize efficiency

While fuel economy isn’t a primary concern for SL63 owners, there are still ways to optimize consumption without sacrificing the driving experience entirely.

One effective strategy is to use the “Comfort” driving mode during daily errands or highway cruising. This mode softens throttle response, encourages earlier upshifts, and minimizes engine braking, all of which contribute to more efficient operation and better fuel economy.

Maintaining consistent speeds on the highway is crucial. Avoid unnecessary acceleration and deceleration, particularly when using cruise control. The SL63’s potent engine can accelerate quickly, but this rapid acceleration is a significant fuel consumer.

Regular maintenance, such as ensuring proper tire inflation and timely oil changes, can also have a subtle but positive impact on fuel economy. An engine that is well-maintained and operating within its optimal parameters will always be more efficient.

Paying attention to your driving style can make a difference. Smooth throttle inputs, anticipating traffic flow, and gentle braking will not only improve fuel economy but also provide a more comfortable ride for occupants. Forceful, abrupt driving will invariably lead to higher fuel consumption.