21 MPG combined is what you get when you want open-air thrills combined with real performance. The 2017 Audi S5 Cabriolet isn’t about hypermiling; it’s about the visceral experience of a turbocharged V6 pushing you through winding roads with the top down. This MPG figure reflects that tradeoff, and the S5’s target buyer understands it.

City and highway performance

The EPA estimates the S5 Cabriolet at 18 MPG in the city and 26 MPG on the highway. The city figure is based on stop-and-go traffic, where the engine constantly works to accelerate the car. The highway number shows what the engine can do when it cruises at a constant speed. The S tronic dual-clutch transmission helps optimize fuel efficiency by selecting the best gear, though it doesn’t completely offset the fuel demands of spirited driving. Don’t expect to see 26 MPG consistently if you’re frequently testing the car’s acceleration on the open road; that figure is more about steady, 70 MPH cruising.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2017 Audi S5 Cabriolet at $2,750. This is based on driving 15,000 miles per year and using national average fuel prices. Remember that this is an estimate; your actual fuel costs may vary depending on your driving, the type of gasoline you use (premium is recommended), and local fuel prices. Someone who mainly drives in the city and has a heavy foot will likely exceed this estimate. Someone who does mainly highway driving and accelerates gently may spend less. $2,750 is a reasonable number for potential owners to consider.

Real-world expectations

The EPA numbers provide a baseline, but real-world fuel economy for the S5 Cabriolet is often lower, especially for drivers who favor performance. Aggressive acceleration, frequent use of Sport mode, and extended idling can all decrease fuel economy. However, drivers who adopt a more relaxed driving style and make good use of the engine’s torque can get closer to the EPA estimates. Tire pressure, ambient temperature, and even traffic can also play a role.

How it compares

The 2017 Audi S5 Cabriolet blends performance with open-air enjoyment. Other high-performance convertibles put the S5’s economy in context. For example, the BMW 440i Convertible with xDrive is rated at 25 MPG combined, close to the Audi. The Mercedes-Benz C43 AMG Cabriolet offers even more power, but delivers a slightly lower 22 MPG combined. These differences can add up. Buyers looking for similar power but prioritizing fuel economy might consider a coupe version of the S5, which could offer slightly better MPG thanks to its lighter weight, or explore S5 MPG across all years. Options and packages can add weight, impacting economy. For a broader look at all vehicles from the manufacturer, you can explore all Audi fuel economy data.

Tips to maximize efficiency

Avoid aggressive acceleration and braking. The S5’s turbocharged engine responds well to a light foot. Smooth acceleration and anticipating traffic flow will help you conserve fuel. Stomping on the accelerator uses a lot more fuel.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, which forces the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the recommended levels, typically found on a sticker inside the driver’s side doorjamb.

Minimize idling. Letting the engine idle wastes fuel. If you’re going to be stopped for more than a minute, consider turning off the engine. Modern cars are designed to restart quickly.

Use cruise control on the highway. Cruise control helps maintain a constant speed, which can improve fuel economy on long highway drives. Avoid using cruise control in hilly areas, as the car may downshift frequently, negating any fuel savings.

Consider using a lighter touch when running accessories. Air conditioning uses a lot of the car’s energy. Be conscious of when you are using the largest energy sucks and try to use them in moderation.