23 MPG combined may not sound like much, but it reflects a balance for the 2018 Audi S5 Cabriolet. This isn’t a Prius; it’s a stylish, open-top grand tourer designed for effortless performance and a premium experience. Those buying an S5 drop-top are prioritizing a thrilling drive and striking design over ultimate fuel efficiency. They understand there is a cost, both literal and figurative, for enjoying the wind in their hair and the responsive surge of a turbocharged V6.

City and highway performance

The EPA estimates the S5 Cabriolet achieves 20 MPG in the city and 29 MPG on the highway. These figures reflect the car’s character. The city MPG indicates the engine’s thirst during stop-and-go driving, where the turbocharger is constantly spooling up and down. The highway MPG, however, shows the benefits of the eight-speed automatic transmission, which allows the engine to cruise at lower RPMs for improved fuel economy. This makes it a fairly reasonable long-distance cruiser, if you resist the urge to constantly dip into the engine’s considerable power reserves.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Audi S5 Cabriolet at $2,500. This calculation is based on driving 15,000 miles per year and using current national average fuel prices. Owners should note that this is an estimate, and your actual fuel costs may vary depending on your driving habits, location, and fuel prices in your area. Still, $2,500 is a substantial sum, highlighting the fact that performance and luxury often come with a price at the pump.

Real-world expectations

While the EPA provides a benchmark, real-world fuel economy can differ significantly. Aggressive driving, frequent short trips, and traffic congestion will all negatively impact the S5’s fuel consumption. Owners who regularly use the car’s performance capabilities, like accelerating hard or engaging Sport mode, should expect to see MPG figures closer to the city rating, even on the highway. However, those who prioritize smooth acceleration and consistent speeds may find themselves exceeding the EPA’s highway estimate.

How it compares

Compared to similarly positioned competitors, the 2018 Audi S5 Cabriolet’s fuel economy lands somewhere in the middle. For example, the BMW 440i Convertible (21 city/32 highway) offers slightly better highway MPG. The Mercedes-Benz C43 AMG Cabriolet, while delivering even greater performance, is thirstier, rated at around 19 city and 27 highway. Looking at other Audi models, you can see all Audi fuel economy data on our dedicated page. The S5 sits comfortably above the economy of high-performance models like the RS5, but behind more fuel-conscious sedans like the A4. Also consider exploring S5 MPG across all years to see how this model compares to previous and later versions.

Tips to maximize efficiency

The Audi S5’s turbocharged engine benefits from smooth and gradual acceleration. Avoid jackrabbit starts and try to anticipate traffic flow to minimize unnecessary braking and acceleration. Using the car’s standard drive select modes can also help optimize fuel usage. Selecting “Comfort” or “Efficiency” mode will remap the throttle response and shift points to prioritize fuel economy over outright performance.

Proper tire inflation is critical for fuel efficiency. Check your tire pressures regularly and ensure they are inflated to the manufacturer’s recommended specifications, typically found on a sticker inside the driver’s side doorjamb. Underinflated tires increase rolling resistance and reduce fuel economy.

Regular maintenance, including oil changes and air filter replacements, helps ensure the engine is running efficiently. A clean air filter allows the engine to breathe easier, while fresh oil reduces friction and improves lubrication. This translates to better fuel economy and a longer lifespan for the engine.

Avoid carrying unnecessary weight in the vehicle. Extra cargo adds strain on the engine and reduces fuel economy, especially in city driving. Remove any items from the trunk or backseat that you don’t need for your daily commute.