18 MPG combined is what buyers expect from a 2026 Audi S8 4.0L V8. This isn’t a frugal commuter; it’s a 563-horsepower executive express, a high-performance luxury sedan built for effortless, continent-crossing speed and ultimate comfort, regardless of what the pump demands. The S8 is for the individual who has long since ascended past concerns about gasoline prices, whose vehicle choice is a statement of capability, luxury, and a deep appreciation for the finer points of automotive engineering, unburdened by everyday pragmaticism.

City and Highway Performance

The S8’s 15 MPG city rating reflects its substantial curb weight, the relentless work of its twin-turbocharged 4.0-liter V8, and its all-wheel-drive system. Stop-and-go traffic is a challenge for any high-output engine, especially one tasked with moving such a substantial and sumptuously appointed sedan. This isn’t a vehicle designed to sip fuel through urban congestion; it’s designed to surge ahead with instant, authoritative power whenever the opportunity arises. On the open road, the S8 truly comes into its own, achieving 24 MPG highway. The ZF 8-speed automatic transmission, renowned for its smooth shifts, allows the powerful V8 to settle into a relaxed, low-RPM cruise, where the turbos are mostly dormant and the engine’s efficiency measures can work their magic. This impressive highway figure speaks to the S8’s long-distance touring prowess, where drivers will cover vast distances in sublime comfort with an engine that feels effortlessly unstressed.

Annual fuel cost

The EPA estimates an annual fuel cost of $3,200 for the 2026 Audi S8. This figure is derived from the assumption of driving 15,000 miles per year, with 45% of those miles in city driving and 55% on the highway, using national average fuel prices. For the S8 owner, this figure represents a minor operational expense, a small component of the total cost of ownership for a vehicle in this segment. They are accustomed to premium costs for premium experiences, whether that’s the vehicle itself, its maintenance, or its fuel. The individual who opts for an S8 prioritizes performance, luxury, and technological sophistication, understanding that those attributes come with a corresponding investment in fuel.

Real-World Expectations

In real-world driving, expecting 18 MPG combined from the S8 is reasonable, but it depends heavily on the driver’s throttle discipline. The immense power and torque of the 4.0-liter V8 are intoxicating, and frequent, enthusiastic use of the accelerator will predictably push fuel economy closer to the 15 MPG city figure, even on roads that aren’t strictly urban. Owners who regularly exploit the S8’s astonishing acceleration, 0-60 mph in under 4 seconds, will see their average MPG dip. Conversely, those who predominantly use the S8 for long, sustained highway journeys, using the adaptive cruise control and predictive efficiency assist, may occasionally exceed the 24 MPG highway rating. This vehicle’s character is fundamentally about delivering an unparalleled driving experience, and its fuel economy is directly proportional to how often that experience is fully unleashed. For more detailed information on S8 MPG across all years, explore our historical data.

How It Compares

The 2026 Audi S8’s fuel economy places it squarely within its high-performance luxury sedan segment. Consider direct competitors: the Mercedes-AMG S 63 E Performance, despite its plug-in hybrid powertrain, typically achieves around 20-22 MPG combined once its electric range is depleted, while its pure V8 counterpart (if available in a similar guise) would likely hover near the S8’s figures. The BMW M760i xDrive, discontinued in its V12 form, would return even lower numbers, and its current highest-performance 7-series variant, the i7 M70 electric, shifts the comparison entirely. For a more traditional V8 competitor, the Lexus LS 500 F Sport, with a less powerful twin-turbo V6, still only manages 21 MPG combined. This demonstrates that the S8’s 18 MPG is not an outlier for a vehicle of its power output and luxury. The buyers in this segment are not cross-shopping with hybrid family sedans; they are evaluating ultimate luxury, performance, and brand prestige. The S8 offers a distinct blend of understated aggression and technological prowess that differentiates it, and its fuel economy is a known quantity for such a powerful V8. For a broader look at all Audi fuel economy data, our database is available.

Tips to maximize efficiency

While an Audi S8 is rarely purchased for its fuel economy, intelligent driving can still yield noticeable improvements. Engaging the “Efficiency” drive mode moderates throttle response and optimizes gear changes, allowing the powerful V8 to operate in its most economical range. This mode also fine-tunes the climate control and other ancillary systems for minimal power draw.

Use the adaptive cruise control with predictive efficiency assist on the highway. This system, when linked to navigation data, can anticipate inclines, declines, and traffic, subtly adjusting speed to conserve momentum and reduce unnecessary braking and acceleration.

Maintain consistent tire pressure. The S8’s large, high-performance tires are critical for handling and safety, but underinflation drastically increases rolling resistance and, consequently, fuel consumption. Regular checks are essential for both efficiency and optimal performance.

Minimize unnecessary weight. While the S8 is a heavy vehicle by design, removing any non-essential items from the trunk reduces the load on the engine, however marginally. Every pound saved contributes to better efficiency, even in a vehicle of this caliber.

Avoid excessive idling. The S8 features an engine start/stop system, but in situations where it might be disabled or in unusually long stops, turning off the engine manually saves fuel. The powerful engine can easily restart without issue when traffic begins to move.