The Mercedes-Benz GLS-Class does 19.2 mpg combined (17.2 city, 22.2 highway), which works out to about $2,000 a year in fuel at $3.20 a gallon and 12,000 miles. Engine choice matters more than you'd think: 3L 6-cyl Hybrid does 20.7 mpg while 4.7L 8-cyl does 16 — a difference of $545 a year. Against other Hybrid cars it sits below the average of 29.8 mpg.
Every Mercedes-Benz GLS-Class engine, compared
Gas mileage on the Mercedes-Benz GLS-Class ranges from 20.7 down to 16 depending on which engine sits under the bonnet — a spread of $545 a year across 3 versions of the same car. Picking the right one often saves more fuel than picking a different car altogether. Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 3L 6-cyl Hybrid | 18.9 / 23.7 | 2020–2026 | $1,855 | |
| 3L 6-cyl | 16.7 / 22 | 2017–2019 | $2,053 | |
| 4.7L 8-cyl | 14 / 18.7 | 2017–2019 | $2,400 |
What that actually costs
The Mercedes-Benz GLS-Class burns a gallon every 19.2 miles, so 12,000 miles takes about 625 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.167 |
| Fuel per year | $2,000 |
| Fuel over five years | $10,000 |
| Against other Hybrid cars | +$711 a year |
| EPA's own estimate | $4,058 a year |
City or highway — who is this car for
The Mercedes-Benz GLS-Class gives up 5 mpg the moment you leave the motorway — 22.2 out there against 17.2 in town, a 29% drop worth $503 a year. A wide gap punishes stop-and-start traffic; a narrow one means the car doesn't care where you drive it.
| Measure | Value | Reading |
|---|---|---|
| City | 17.2 mpg | $2,233 a year if you only drive in town |
| Highway | 22.2 mpg | $1,730 a year if you mostly commute |
| Gap | +5 mpg (29%) | Typical for its type |
How the GLS-Class changed over the years
The GLS-Class peaked in 2026 at 21 mpg (19 city, 24 highway) and was at its thirstiest in 2019 at 17 — 4 mpg apart, or $430 a year in fuel between buying one year and the other. The 2026 car does 21. Jumps usually mark a new generation or a new engine; dips often mean a heavier body or added all-wheel drive.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 2026 | 19 / 24 | 1 | $1,829 | |
| 2025 | 19 / 24 | 1 | $1,829 | |
| 2024 | 19 / 24 | 1 | $1,829 | |
| 2023 | 18 / 23 | 1 | $1,920 | |
| 2022 | 18 / 24 | 1 | $1,920 | |
| 2021 | 20 / 24 | 1 | $1,829 | |
| 2020 | 19 / 23 | 1 | $1,829 | |
| 2019 | 15 / 20.5 | 2 | $2,259 | |
| 2018 | 15.5 / 20.5 | 2 | $2,194 | |
| 2017 | 15.5 / 20 | 2 | $2,194 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 13 EPA ratings of the Mercedes-Benz GLS-Class — 3 engines across 2017–2026. The mileage is EPA's laboratory figure, unchanged; the yearly bill is ours, at 12,000 miles and $3.20 a gallon, against EPA's own estimate of $4,058. Full method.
Frequently asked questions
What mpg does the Mercedes-Benz GLS-Class get?
19.2 mpg combined on average — 17.2 in the city and 22.2 on the highway, per EPA ratings across 2017–2026.
How much does a Mercedes-Benz GLS-Class cost in fuel per year?
About $2,000 at 12,000 miles and $3.20 a gallon — roughly $10,000 over five years, or 0.167 dollars a mile.
Which GLS-Class engine is the most economical?
The 3L 6-cyl Hybrid at 20.7 mpg, against 16 for the 4.7L 8-cyl — a difference of about $545 a year.
Is the GLS-Class good on fuel compared with similar cars?
Against other Hybrid cars it sits below the average of 29.8 mpg, computed across 1162 ratings.
Are these real-world GLS-Class figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the Mercedes-Benz GLS-Class is $4,058 against the $2,000 we compute at 12,000 miles. Expect a little worse in practice: the spread between the 21 and 16 mpg versions of this car is smaller than the spread between two drivers of the same one.
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