Mercedes-Benz GLS450 4matic
21 MPG The 2026 Mercedes-Benz GLS450 4matic is EPA-rated at 21 MPG combined (19 city / 24 highway). Over 15,000 miles a year that is about 714 gallons, $2286 a year in fuel, or $0.152 per mile at $3.20/gal.
Across its full 2017–2026 run it averages 20.1 MPG, improving by 2 MPG over 10 model years.
Running cost at different fuel prices and mileages
The figure everyone actually wants, and the one the EPA does not publish — because it depends on a fuel price no agency will commit to.
| Fuel price | Per mile | 10,000 mi/yr | 15,000 mi/yr | 20,000 mi/yr |
|---|---|---|---|---|
| $2.50/gal | $0.119 | $1190 | $1786 | $2381 |
| $3.00/gal | $0.143 | $1429 | $2143 | $2857 |
| $3.20/gal | $0.152 | $1524 | $2286 | $3048 |
| $3.50/gal | $0.167 | $1667 | $2500 | $3333 |
| $4.00/gal | $0.190 | $1905 | $2857 | $3810 |
| $4.50/gal | $0.214 | $2143 | $3214 | $4286 |
| $5.00/gal | $0.238 | $2381 | $3571 | $4762 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 2026 | 21 MPG | 19 | 24 | $3650 | 428 | 1 |
| 2025 | 21 MPG | 19 | 24 | $3650 | 428 | 1 |
| 2024 | 21 MPG | 19 | 24 | $3650 | 428 | 1 |
| 2023 | 20 MPG | 18 | 23 | $3850 | 433 | 1 |
| 2022 | 20 MPG | 18 | 24 | $3850 | 433 | 1 |
| 2021 | 21 MPG | 20 | 24 | $3650 | 414 | 1 |
| 2020 | 21 MPG | 19 | 23 | $3650 | 429 | 1 |
| 2019 | 18 MPG | 16 | 22 | $4300 | 488 | 1 |
| 2018 | 19 MPG | 17 | 22 | $4050 | 477 | 1 |
| 2017 | 19 MPG | 17 | 22 | $4050 | 477 | 1 |
Where a model year offered several engines or drivetrains, the figure is the average across all EPA-tested trims that year — the trim count is shown so you can see how much averaging is involved.
How it compares in its class
Among the 105 standard sport utility vehicle 4wd models tracked here, the Mercedes-Benz GLS450 4matic ranks 17 on current figures, against a class average of 19.7 MPG.
Closest more-efficient alternatives in the same class: Ford Explorer AWD (21.5), Jeep Grand Cherokee L 4WD (21.5), Audi Q7 (22), BMW X7 xDrive40i (22), Subaru Ascent (22).
Tailpipe CO₂ is rated at 428 grams per mile, which works out to roughly 6.4 tonnes a year at 15,000 miles.
Questions
What MPG does the Mercedes-Benz GLS450 4matic get?
The 2026 Mercedes-Benz GLS450 4matic is rated at 21 MPG combined by the EPA — 19 city and 24 highway. Across all 10 model years in the database it averages 20.1 MPG, ranging from 18 to 21 depending on year and trim.
How much does a Mercedes-Benz GLS450 4matic cost in fuel per year?
At 21 MPG and 15,000 miles a year, it burns about 714 gallons — roughly $2286 a year with fuel at $3.20 a gallon, or $0.152 per mile. The EPA's own published annual figure for the 2026 model is $3650.
Has the Mercedes-Benz GLS450 4matic become more efficient over time?
Yes. It has gone from 19 MPG in 2017 to 21 in 2026 — an improvement of 2 MPG, or 11% across 10 model years.
Is the Mercedes-Benz GLS450 4matic efficient for its class?
It ranks 17 of 105 in the Standard Sport Utility Vehicle 4WD class on current figures, against a class average of 19.7 MPG. That is 1.3 better than typical for the class.
EPA test figures from fueleconomy.gov. Cost per mile and annual fuel spend are computed at a reference price of $3.20 per gallon — use your own price. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.