16 MPG combined isn’t going to win any fuel economy awards, but for the 2019 Mercedes-Benz GLS550 4matic, it’s simply part of the cost. This isn’t a vehicle bought by penny-pinchers; this is a statement of effortless capability wrapped in leather and technology, aimed at affluent families who prioritize space, luxury, and that three-pointed star on the hood. They’re more concerned with the ease of merging onto the highway with seven passengers than they are with squeezing out an extra mile per gallon.

City and highway performance

The EPA estimates 14 MPG in the city and 19 MPG on the highway. The city figure is understandable given the GLS550’s weight and the demands of frequent stop-and-go driving. The 19 MPG highway figure is achievable in real-world conditions, especially on longer journeys where the smooth-shifting 9-speed automatic transmission can settle into its higher gears and the powerful 4.7L V8 operates with minimal effort. Remember that this engine is designed for effortless power delivery, not maximizing fuel burn, so aggressive acceleration or sustained high speeds will negatively impact that highway number.

Annual fuel cost

The Environmental Protection Agency estimates that the annual fuel cost for the 2019 Mercedes-Benz GLS550 4matic is $3,600. This figure is based on driving 15,000 miles per year, using a national average fuel price. Of course, your actual fuel costs will vary depending on your driving habits, local fuel prices, and the specific conditions in which you operate the vehicle. But this $3,600 figure provides a useful benchmark for understanding the potential cost of ownership relating to fuel consumption.

Real-world expectations

While the EPA figures provide a baseline, real-world MPG will vary. Drivers who frequently haul passengers, tow trailers, or primarily drive in congested urban environments will likely see figures below the EPA estimates. Conversely, those who spend more time on the open road, driving conservatively, may achieve numbers closer to, or even slightly above, the 19 MPG highway rating. It all comes down to driving style and operational demands. Remember all Mercedes Benz fuel economy data can be found on our site.

How it compares

The GLS550 isn’t exactly a leader in fuel efficiency compared to its competitors. The BMW X7 xDrive40i, with its turbocharged inline-six, achieves a combined 22 MPG. The Lexus LX 570, which is known to use a lot of gas, still manages a combined 15 MPG, only slightly behind the GLS550. Even the Cadillac Escalade, with its 6.2L V8, lands around 17 MPG combined in comparable configurations. For buyers intensely focused on fuel economy, the plug-in hybrid variants of the Volvo XC90 offer an alternative, though with compromises in outright power compared to the GLS550’s V8. These comparisons matter less to the typical GLS550 buyer, but for those even peripherally concerned with fuel costs, the alternatives should be considered. See the GLS550 MPG across all years.

Tips to maximize efficiency

While the GLS550 isn’t designed for hypermiling, there are still a few things you can do to improve its fuel economy. Avoid aggressive acceleration and braking. The smooth and responsive nature of the V8 doesn’t require you to stomp on the accelerator to achieve decent speed, and gentle braking allows the vehicle’s momentum to be maintained.

Ensure that your tires are properly inflated. Underinflated tires increase rolling resistance, which puts a greater strain on the engine and reduces fuel efficiency. Check your tire pressure regularly and inflate them to the recommended levels, found on a sticker inside the driver’s doorjamb.

Minimize unnecessary weight. Carrying around extra cargo in the GLS550’s spacious interior or cargo area will decrease fuel economy. Remove any items that you don’t need to be carrying on a regular basis. This includes anything from sports equipment to tools.

Plan your trips to avoid rush hour traffic. Stop-and-go driving consumes significantly more fuel than driving at a consistent speed on the open road. Where possible, try to schedule your trips during off-peak hours to minimize time spent idling in traffic.

Use cruise control on the highway. Maintaining a constant speed helps to improve fuel economy by avoiding unnecessary acceleration and deceleration. Just be sure to use cruise control responsibly, and be prepared to disengage it in changing traffic conditions.