21 MPG combined is what you get with the 2018 Audi RS 5. It’s the fuel economy figure the buyer accepts as a trade-off for fast performance, all-weather capability, and understated aggression. This isn’t a grocery-getter disguised as a sports car; it’s an engineered performance machine that is surprisingly usable every day. Those who want ultimate efficiency won’t even look at it, but for the enthusiast who needs a daily driver that can handle a back road, the RS 5’s need for premium fuel is part of the deal.

City and highway performance

The EPA estimates the 2018 Audi RS 5 will achieve 18 MPG in the city and 26 MPG on the highway. These figures reflect the car’s personality. The city number suggests that stop-and-go traffic and the temptation to use the car’s immediate torque will reduce fuel consumption. The highway figure hints at the RS 5’s ability to cruise comfortably at higher speeds, where the efficient 8-speed automatic transmission and well-tuned engine management system can work. However, even on the open road, aggressive passing and time above the speed limit will quickly lower that 26 MPG figure.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Audi RS 5 at $2,750. This figure is based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway, using national average fuel prices for premium gasoline. This is just an estimate, and your actual fuel costs will vary depending on your driving habits, local fuel prices, and the specific conditions in which you drive. Drivers who spend most of their time in urban environments can expect to exceed this figure, while those with a lighter touch and more highway miles may do slightly better.

Real-world expectations

While the EPA provides a baseline, real-world fuel economy often differs from official estimates. Owners of the 2018 Audi RS 5 report figures that are within a few MPG of the EPA estimates, but the range of reported figures varies. Those who resist the urge to use the car’s power can achieve numbers close to the EPA’s, while others, influenced by the acceleration and exhaust note, will likely see significantly lower results. The RS 5’s fuel economy depends on driving style, and using the accelerator too much will lead to trips to the gas station.

How it compares

Compared to its direct competitors, the 2018 Audi RS 5 is in the middle in terms of fuel economy. The BMW M4, for example, is rated at 18 MPG city and 25 MPG highway, making it very similar in fuel usage. The Mercedes-AMG C63 Coupe, with its more powerful V8 engine, is rated at a less efficient 17 MPG city and 24 MPG highway. The fact that RS 5 MPG across all years lands somewhere in the middle of this group is acceptable to a buyer who wants the Audi’s combination of performance, all-weather capability (thanks to its Quattro all-wheel-drive system), and understated design. Someone seeking efficiency might consider the Lexus RC 350 F Sport, which offers similar styling but a less powerful engine and a more fuel-friendly 20 MPG city and 28 MPG highway. But these are different cars bought for different reasons, and anyone cross-shopping with the Lexus is likely making a compromise.

Tips to maximize efficiency

Anticipate traffic flow and avoid unnecessary hard acceleration. The RS 5’s powerful engine responds instantly to throttle input, so smooth and steady driving will save fuel. Use the car’s selectable driving modes; the “Comfort” or “Efficiency” mode will optimize the engine and transmission settings for fuel economy.

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

Avoid extended idling. Modern engines warm up quickly, so there’s no need to let the car idle for more than a minute or two, even in cold weather. Prolonged idling wastes fuel and contributes to emissions.

Keep up with scheduled maintenance. A well-maintained engine is a more efficient engine. Regular oil changes, air filter replacements, and spark plug checks will ensure that your RS 5 is running well.

Minimize aerodynamic drag. Removing roof racks or cargo carriers when they’re not in use can improve fuel economy, especially at highway speeds. Also, avoid driving with the windows open at high speeds, as this increases drag and reduces efficiency.