BMW X7 vs Mercedes-Benz GLS-Class: fuel economy and fuel cost
In model year 2026 the BMW X7 is the cheaper of the two to fuel: about $3,560 a year for its lowest-cost configuration (X7 xDrive40i, 23 MPG combined), against $3,860 for the Mercedes-Benz GLS-Class (GLS450 4matic, 21 MPG combined). That is $300 a year, or $1,500 over five years.
Both are classed as Standard SUVs by the EPA. Costs assume 15,000 miles a year and the same fuel and electricity prices for both vehicles, using the EPA combined rating (55% city, 45% highway). Each figure is rounded to $10 and every difference is calculated from the rounded values.
The EPA is still publishing model year 2027 ratings, so this page compares model year 2026, the latest complete year.
- Hybrid
- Standard SUVs
BMW X7
Lowest fuel cost configuration
X7 xDrive40i
$23.73 per 100 miles
15,000 mi/yr, same fuel prices
3 configurations in MY2026
- Hybrid
- Standard SUVs
Mercedes-Benz GLS-Class
Lowest fuel cost configuration
GLS450 4matic
$25.73 per 100 miles
15,000 mi/yr, same fuel prices
4 configurations in MY2026
What the fuel costs
Annual fuel cost of the lowest-cost configuration
- BMW X7$3,560 a year · $23.73 per 100 mi
- Mercedes-Benz GLS-Class$3,860 a year · $25.73 per 100 mi
Difference per year
$300
BMW X7 costs less to fuel
Over 5 years
$1,500
$300 a year × 5, 15,000 mi/yr, same fuel prices
Head to head, MY2026
| Measure | BMW X7 | Mercedes-Benz GLS-Class |
|---|---|---|
| Lowest-cost configuration | X7 xDrive40i | GLS450 4matic |
| Powertrain | Hybrid | Hybrid |
| Combined rating | 23 MPG (better) | 21 MPG |
| City rating | 21 MPG (better) | 19 MPG |
| Highway rating | 25 MPG (better) | 24 MPG |
| Annual fuel cost | $3,560/yr (better) | $3,860/yr |
| Cost per 100 miles | $23.73 (better) | $25.73 |
| Annual cost range, all configurations | $3,560–$4,640 | $3,860–$5,310 |
| Configurations in MY2026 | 3 | 4 |
| EPA class | Standard SUVs | Standard SUVs |
Best configuration by powertrain
| Powertrain | BMW X7 | Mercedes-Benz GLS-Class |
|---|---|---|
| Hybrid | 23 MPG · $3,560/yr X7 xDrive40i | 21 MPG · $3,860/yr GLS450 4matic |
Each cell shows the combined rating and the annual fuel cost of the lowest-cost configuration with that powertrain.
Where each one comes out ahead
Generated from the numbers above, comparing the lowest fuel cost configurations. No subjective judgements.
BMW X7
- Lower annual fuel cost: $3,560 vs $3,860
- Higher combined rating: 23 MPG vs 21 MPG
- Higher city rating: 21 MPG vs 19 MPG
- Higher highway rating: 25 MPG vs 24 MPG
Mercedes-Benz GLS-Class
Not ahead on any measure listed here.
Year by year
| Model year | BMW X7 | Mercedes-Benz GLS-Class | ||
|---|---|---|---|---|
| Combined | Per year | Combined | Per year | |
| 2026 | 17–23 MPG | $3,560–$4,640 | 15–21 MPG | $3,860–$5,310 |
| 2025 | 17–22 MPG | $3,650–$4,640 | 15–21 MPG | $3,860–$5,350 |
| 2024 | 17–22 MPG | $3,600–$4,640 | 16–21 MPG | $3,860–$5,180 |
| 2023 | 17–22 MPG | $3,600–$4,640 | 16–20 MPG | $3,950–$5,070 |
| 2022 | 17–21 MPG | $3,780–$4,720 | 15–20 MPG | $3,940–$5,190 |
| 2021 | 17–21 MPG | $3,780–$4,690 | 16–21 MPG | $3,750–$5,050 |
| 2020 | 17–22 MPG | $3,690–$4,660 | 18–21 MPG | $3,880–$4,430 |
| 2019 | 17–22 MPG | $3,690–$4,590 | 15–18 MPG | $4,410–$5,430 |
Earlier model years are costed with today's fuel prices, so the table shows how each model's efficiency changed, not what fuel cost at the time. Ranges cover every configuration of that model year.
Frequently asked questions
Which is cheaper to fuel, the BMW X7 or the Mercedes-Benz GLS-Class?
The BMW X7 is cheaper: about $3,560 a year against $3,860 for the Mercedes-Benz GLS-Class, a difference of $300 a year. That compares the lowest-cost configuration of each in model year 2026 at 15,000 miles a year with the same fuel prices.
How much would the BMW X7 save over five years?
About $1,500 ($300 a year for five years), assuming 15,000 miles a year and the same fuel prices. Your total depends on how much you drive and on local prices; see fuel cost by state.
Which has the better fuel economy rating, the BMW X7 or the Mercedes-Benz GLS-Class?
The BMW X7 is rated 23 MPG combined against 21 MPG for the Mercedes-Benz GLS-Class. City: 21 MPG vs 19 MPG. Highway: 25 MPG vs 24 MPG. These are the EPA ratings of each model's lowest-cost configuration.
How is the annual fuel cost calculated?
Distance of 15,000 miles a year at the EPA combined rating (55% city, 45% highway). Gasoline is priced at $4.36/gal (EIA U.S. average for regular, Sep 2026) and electricity at 18.3¢/kWh (EIA U.S. residential average, Jul 2026); premium and diesel configurations use their own EIA prices. Each result is rounded to $10, and differences are calculated from the rounded figures.
Are the BMW X7 and the Mercedes-Benz GLS-Class in the same class?
Yes. The EPA classes both as Standard SUVs.
Explore these cars
- BMW X7: ratings, trims and every model year
- Mercedes-Benz GLS-Class: ratings, trims and every model year
- 2026 BMW X7: all configurations
- 2026 Mercedes-Benz GLS-Class: all configurations
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