22 MPG combined in the 2018 Audi A8 L with the 3.0L six-cylinder engine isn’t going to win any fuel efficiency awards, but it’s a perfectly acceptable figure for what this car represents: a supremely comfortable, technologically advanced, and subtly powerful long-wheelbase luxury sedan. Buyers in this segment prioritize refinement and presence over outright fuel savings, and the A8 L delivers those qualities in spades. They are looking for rear seat legroom and a quiet ride, not a Prius. The fuel economy is simply the price of admission.

City and highway performance

The EPA estimates for the 2018 A8 L 3.0T put city driving at 19 MPG and highway cruising at 29 MPG. The difference between these figures shows the A8 L’s nature. It’s a heavy car, so stop-and-go city traffic will take a toll. The standard all-wheel drive system adds weight and consumes energy as well. The compliant suspension, refined engine, and exceptionally quiet cabin transform long highway journeys into relaxing experiences. The advanced eight-speed automatic transmission helps, keeping the engine in its most efficient range when possible. While 29 MPG on the open road is good, the A8 L’s overall efficiency suffers when it is stuck in urban environments.

Annual fuel cost

According to the EPA, the annual fuel cost for the 2018 Audi A8 L 3.0T is $2,650. This figure is based on driving 15,000 miles per year, using the EPA’s combined MPG rating, and the national average fuel prices at the time of calculation. Individual fuel expenses will vary based on driving habits, local fuel costs, and the type of fuel used (premium fuel is highly recommended for optimal performance). Considering the overall expense of owning a flagship luxury sedan like the A8 L, this fuel cost is a relatively manageable part of the ownership picture for typical buyers.

Real-world expectations

While the EPA estimates provide a standardized benchmark, real-world MPG can vary depending on several things. Aggressive driving, frequent short trips, and carrying extra weight can all negatively impact fuel economy. Gentle acceleration, consistent highway speeds, and proper tire inflation can help improve MPG. Owners who frequently drive in congested city environments may see figures closer to the 19 MPG city rating. Those who primarily use the A8 L for long highway commutes may achieve numbers exceeding the 29 MPG highway estimate. The car’s onboard computer provides real-time and historical fuel economy data to help drivers monitor their consumption.

How it compares

The A8 L’s fuel economy lands it roughly in the middle of its competitive set. The BMW 740i, also equipped with a 3.0L inline-six, achieves similar figures. Mercedes-Benz offers the S450, which earns comparable MPG figures. These established rivals generally cluster within a few MPG of each other. Opting for a V8 engine in any of these cars will deliver more power, but fuel economy will plummet to the mid-teens in the city. Buyers considering the A8 L will likely cross-shop these alternatives, but fuel economy is likely just one factor among many, including brand preference, features, and overall driving experience. Review A8 MPG across all years to better understand how mileage may change by model year.

Tips to maximize efficiency

One of the simplest ways to save fuel in the A8 L is to drive smoothly and avoid aggressive acceleration. The 3.0T engine provides ample power, so there’s no need to constantly push the car to its limits. Gentle acceleration and anticipating traffic flow will prevent abrupt stops and starts, maximizing fuel efficiency.

Make sure that your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly and maintain the recommended levels, which can be found on a sticker inside the driver’s side doorjamb.

Minimize idling time. If you’re stopped for more than a minute or two, turn off the engine. Modern cars like the A8 L are designed to restart quickly and efficiently, and the fuel saved by avoiding prolonged idling can add up over time. Many A8s come standard with auto stop/start.

Use the car’s drive mode selector to your advantage. The A8 L typically offers various driving modes, including an “Efficiency” or “Comfort” mode that optimizes settings for maximum fuel economy. Selecting these modes can adjust throttle response and shift points to improve MPG. Learn how all Audi fuel economy data compares year-to-year.