18 MPG combined isn't going to win any awards, but the 2022 Mercedes-Benz GLS580 doesn't play that game. This is a supremely comfortable, immensely capable, and technologically advanced three-row SUV. Its target demographic, successful professionals and families who prioritize space, luxury, and power, understands the trade-off. They're not necessarily insensitive to fuel costs, but it's rarely the deciding factor in choosing a vehicle that carries so much prestige.

City and highway performance

The EPA estimates put the GLS580 at 16 MPG in the city and 21 MPG on the highway. The city figure reflects the stop-and-go nature of urban driving, where the GLS580's hefty curb weight and powerful 4.0-liter twin-turbo V8 require more fuel to get moving from a standstill. The highway number, however, demonstrates the engine's ability to cruise efficiently once up to speed. The smooth-shifting 9-speed automatic transmission helps keep the engine in its optimal rev range, contributing to the reasonable highway fuel consumption for its class.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2022 Mercedes-Benz GLS580 at $3,200. This figure is based on driving 15,000 miles per year and using the national average fuel price for premium gasoline, which this vehicle requires. Individual fuel costs will vary depending on driving habits, local fuel prices, and the actual number of miles driven annually.

Real-world expectations

While the EPA provides a standardized estimate, real-world MPG often differs based on individual driving habits and conditions. Expect to see numbers slightly below the EPA estimates if you frequently drive in congested city traffic or have a heavy foot. Conversely, longer highway trips at consistent speeds might yield numbers closer to, or even slightly above, the 21 MPG rating. The GLS580's onboard computer provides real-time and average fuel economy data, enabling drivers to monitor their consumption and adjust their driving style accordingly.

How it compares

Compared to its competitors, the GLS580's fuel economy falls within the expected range for a large, powerful luxury SUV. The BMW X7 M50i, with a similar engine configuration, achieves around 16 MPG combined. The Land Rover Range Rover P530, another contender in this segment, offers similar performance but with slightly worse fuel economy, typically around 17 MPG combined. The Cadillac Escalade, while offering more interior space, lands around 16 MPG combined with its standard V8. For many buyers, the slight differences in MPG are less significant than factors like brand prestige, interior appointments, and driving experience. Those seeking better fuel economy in the Mercedes-Benz lineup can explore all all Mercedes Benz fuel economy data, which includes hybrid and smaller engine options in other models.

Tips to maximize efficiency

Avoid aggressive acceleration. The GLS580's powerful V8 responds eagerly to throttle inputs, but each burst of acceleration consumes a significant amount of fuel. Smooth, gradual acceleration is key to maximizing efficiency, especially around town.

Use cruise control on the highway. Maintaining a consistent speed is important for fuel economy. Cruise control not only helps prevent speeding but also optimizes the engine's performance for steady-state driving.

Ensure 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 inflate them to the recommended levels listed on the doorjamb sticker.

Minimize idling. Excessive idling, especially with the vehicle's luxury features running, burns fuel without covering any distance. If you anticipate a prolonged stop, turn off the engine.

Keep up with scheduled maintenance. A well-maintained engine runs more efficiently. Follow the recommended maintenance schedule outlined in the owner's manual, including regular oil changes, air filter replacements, and spark plug inspections. Owners can also review GLS580 MPG across all years to observe how various model years have performed.