16 MPG combined isn’t a typo. It’s the reality of owning a 2018 Mercedes-Benz AMG S65 Convertible. This is not a car bought for its fuel efficiency. It’s a monument to excess, a rolling celebration of twelve cylinders producing an obscene amount of power, and a statement that fuel costs are simply not a concern. The S65 Convertible exists for those who prioritize handcrafted luxury, blistering acceleration, and the visceral thrill of a twin-turbocharged V12 over contributing to a greener planet. They likely have other cars in their stable for errands and road trips.

City and highway performance

The official EPA figures show a stark contrast between city and highway driving. You can expect 14 MPG in city conditions. Stop-and-go traffic relentlessly punishes the S65’s thirst for premium fuel, as the massive engine idles and accelerates its considerable weight from a standstill. Out on the open highway, the number improves to 21 MPG. This is still far from economical but reflects the engine operating at a more relaxed pace, in higher gears, and with less aggressive throttle inputs. Even on the highway, though, the sheer power on tap makes resisting the urge to accelerate hard remarkably difficult, which impacts fuel economy. The seven-speed automatic transmission, while smooth and responsive, isn’t optimized for ultimate fuel savings, further contributing to the relatively low MPG.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Mercedes-Benz AMG S65 Convertible at $3,600. This figure is based on driving 15,000 miles per year, with an assumed fuel price reflecting national averages. Keep in mind this is just an estimate. If you drive more aggressively, live in an area with higher fuel prices, or exceed the 15,000-mile mark, your actual fuel costs will likely be significantly higher. For perspective, $3,600 is a substantial sum, more than some people spend on an entire used car. But buyers of the S65 Convertible aren’t losing sleep over slightly fluctuating fuel prices.

Real-world expectations

Forget about achieving the EPA numbers consistently. In the real world, expect slightly lower figures, especially if you enjoy the car’s capabilities. The sheer pleasure of unleashing the V12’s power is often too tempting to resist. The S65 isn’t designed for gentle cruising, and its drivers are unlikely to prioritize fuel conservation over performance. Factors like traffic congestion, weather conditions, and even tire pressures can subtly degrade fuel economy in day-to-day usage. While some owners may diligently track their MPG, many won’t concern themselves with anything beyond filling the tank whenever the low-fuel warning illuminates.

How it compares

The AMG S65 Convertible resides in a small and rarefied segment. Direct comparisons are difficult, but let’s consider a few alternatives, understanding none offer the exact same blend of attributes. The Bentley Continental GT Convertible achieves roughly 15 MPG combined with its W12 engine. The less powerful, but still potent, AMG S63 Convertible with its V8 manages around 19 MPG combined, a noticeable improvement. And while not a convertible, the Porsche Panamera Turbo S E-Hybrid offers stunning performance and a combined EPA rating of 22 MPG thanks to its plug-in hybrid powertrain. These comparisons show there are definitely choices that deliver greater efficiency within the luxury performance segment, but the unique character and cachet of the AMG S65 often outweigh rational fuel considerations for its target buyer.

Tips to maximize efficiency

While outright fuel efficiency isn’t the S65’s forte, there are a few things you can do to minimize its thirst. Gentle acceleration is key. Avoid stomping on the accelerator pedal unless you truly need the car’s immense power. Smooth, progressive throttle inputs will allow the engine to operate more efficiently, especially in city driving.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which forces the engine to work harder and consume more fuel. Check your tire pressures regularly and maintain them at the recommended levels, found on a sticker inside the driver’s side door.

Planning your journeys can also improve MPG. Aim for routes that minimize stop-and-go traffic and allow for consistent cruising speeds. Avoiding rush hour and congested areas can make a small but noticeable difference.

Regular maintenance can also help. Make sure your S65 is properly serviced, including oil changes, air filter replacements, and spark plug maintenance. A well-maintained engine runs more efficiently. For all Mercedes Benz fuel economy data, see our other pages.

Finally, be mindful of your driving style. While tempting, resist the urge to constantly engage in aggressive acceleration and high-speed driving. Enjoy the car’s power responsibly, and you’ll see a small improvement in fuel economy. Check out other AMG MPG across all years.