19 MPG combined is the reality for anyone considering a 2018 Audi A8 L with the 4.0L V8. It’s not a number that will excite those looking for less gas, but fuel efficiency is likely not the most important thing for the buyer seeking top-tier Audi luxury in its extended wheelbase form. These are executives, entrepreneurs, and individuals who value space, comfort, and effortless power. They’re looking for a sanctuary on wheels, a mobile boardroom, and a statement of success, and the A8 L delivers, even if it demands a little more from the fuel pump.

City and highway performance

The A8 L 4.0T doesn’t pretend to be a fuel sipper. Its EPA ratings state the trade-off for its power: 16 MPG in the city and 26 MPG on the highway. The city figure reflects the toll of stop-and-go traffic, showing how the engine needs to work harder in these conditions. The highway figure, while better, reflects the reality of a large, powerful engine moving a heavy car at higher speeds. Expect to see figures nearer to 26 MPG only on flat ground at constant speeds; any spirited driving or hill climbing will bring that number down.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Audi A8 L 4.0T at $3,050. This figure is based on driving 15,000 miles per year, with 45% of those miles driven in the city and 55% on the highway. The calculation also uses the national average fuel price at the time of the estimate. Your actual fuel cost may vary depending on your driving habits, where you live, and fluctuating fuel prices. However, the $3,050 figure provides a benchmark against which to compare this car to others.

Real-world expectations

The EPA figures are a good starting point, but real-world MPG can vary considerably. Factors like driving style, traffic conditions, and even tire pressure can impact fuel consumption. Aggressive acceleration and hard braking will lower your MPG. Keeping your tires properly inflated and performing regular maintenance will help you stay closer to the EPA estimates. It is common for drivers to see figures slightly below the EPA averages in mixed driving conditions, especially if they regularly use the V8’s power.

How it compares

The A8 L 4.0T exists in a competitive segment. The BMW 750i xDrive, with its 4.4L V8, offers similar performance but achieves a slightly better 20 MPG combined. The Mercedes-Benz S560, also packing a 4.0L V8, mirrors the Audi’s 19 MPG. A Porsche Panamera 4S, while sportier, still manages 21 MPG combined with its 2.9L V6.

These small differences matter to those who cross-shop these flagship sedans, but the A8 buyer is often prioritizing the blend of luxury, technology, and understated style that Audi delivers. You can also see A8 MPG across all years to get a sense of long term gas mileage trends.

Tips to maximize efficiency

Use the A8’s drive select modes. The “Efficiency” setting optimizes the engine and transmission for fuel conservation. It reduces throttle response and shifts gears earlier, encouraging a more relaxed driving style. This won’t turn the A8 into a Prius, but it can make a noticeable difference on long highway journeys.

Avoid excessive idling. Letting the engine run while waiting for someone or sitting in traffic wastes fuel. If you anticipate being stationary for more than a minute, turn off the engine. The A8’s start-stop system makes restarts very smooth.

Pay attention to tire pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder. Check your tire pressure regularly and maintain the recommended levels indicated on the door jamb. This is a simple step that can improve fuel economy.

Minimize aerodynamic drag. Remove any unnecessary items from the roof or trunk that could create drag. Even open windows at highway speeds can negatively impact fuel efficiency. Using the climate control system strategically, rather than constantly running it at full blast, will also save fuel.

Plan your routes strategically. Avoiding congested areas and choosing routes with fewer stop-and-go situations will help you maintain a more consistent speed and reduce fuel consumption. Use navigation apps to find the most efficient route, taking into account real-time traffic conditions. You can also browse all Audi fuel economy data to see how the A8 compares to other models from the brand.