Mazda CX-30 vs Mercedes-Benz GLB-Class: Specs Compared
Also searched as Mercedes-Benz GLB-Class vs Mazda CX-30 specs — both orientations show this same side-by-side comparison.
The Mazda CX-30 is the more efficient of the two: it reaches 29 mpg combined versus 28 mpg for the Mercedes-Benz GLB-Class, a 1 mpg advantage and costs about $600 less per year to fuel.
Across 4 measured categories, the Mazda CX-30 leads in 4. Figures are EPA test data, not manufacturer claims.
2020–2026
Mazda CX-30
Small Sport Utility Vehicle 4WD · 19 configurations
2020–2026
Mercedes-Benz GLB-Class
Small Sport Utility Vehicle 4WD · 20 configurations
Head-to-head specifications
| Metric | Mazda CX-30 | Mercedes-Benz GLB-Class |
|---|---|---|
| Best combined MPG | 29 mpg ✓ | 28 mpg |
| Best city MPG | 26 mpg ✓ | 25 mpg |
| Best highway MPG | 33 mpg | 33 mpg |
| Lowest annual fuel costEPA estimate at 15,000 miles per year | $2,100 ✓ | $2,700 |
| Lowest CO2 output | 309 g/mi ✓ | 311 g/mi |
| Engines offered | SIDI, SIDI; With Cylinder Deactivation | SIDI; Mild Hybrid, SIDI |
| Transmissions | Automatic (S6) | Automatic (AM8) |
| Drivetrains | 4-Wheel Drive, Front-Wheel Drive | Front-Wheel Drive, All-Wheel Drive, 4-Wheel Drive |
| Fuel types | Regular | Premium |
| EPA class | Small Sport Utility Vehicle 4WD | Small Sport Utility Vehicle 4WD |
| Years covered | 2020–2026 | 2020–2026 |
| Configurations on record | 19 | 20 |
Source: EPA fuel economy records via fueleconomy.gov. Best-case values across all recorded configurations for each model.
Mazda CX-30 vs Mercedes-Benz GLB-Class dimensions and size
The Mercedes-Benz GLB-Class is 9.4 inches longer than the Mazda CX-30 on a wheelbase 7.1 inches longer, and 416.7 lbs heavier. Both clear the roughly 200 inches of usable length in a standard single garage bay.
| Dimension | Mazda CX-30 (2026) | Mercedes-Benz GLB-Class (2026) | Difference |
|---|---|---|---|
| Length | 172.8 in | 182.3 in | 9.4 in |
| Width (excl. mirrors) | 70.9 in | 72 in | 1.2 in |
| Height | 61.8 in | 66.5 in | 4.7 in |
| Wheelbase | 104.3 in | 111.4 in | 7.1 in |
| Curb weight | 3,342 lbs | 3,759 lbs | 417 lbs |
Width excludes mirrors; add 8–12 inches for mirrors out. Figures are for the newest model year on record for each vehicle. See both drawn to scale.
Mazda CX-30 vs Mercedes-Benz GLB-Class: what the numbers mean
Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Mazda CX-30 burns about $2,100 of fuel annually against $2,700 for the Mercedes-Benz GLB-Class. That $600 yearly gap compounds to roughly $3,000 over five years and $4,800 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.
City versus highway split: the Mazda CX-30 is the stronger commuter at 26 mpg city, while the Mercedes-Benz GLB-Class pulls ahead on the interstate at 33 mpg highway. If most of your driving is stop-and-go traffic the city figure is the one to weigh; for long-distance highway mileage the reverse is true, and the two vehicles effectively swap places depending on how you drive.
Powertrain choice: the Mazda CX-30 is recorded with 2 distinct engine configurations (SIDI, SIDI; With Cylinder Deactivation), the Mercedes-Benz GLB-Class with 2 (SIDI; Mild Hybrid, SIDI). Across 19 recorded Mazda CX-30 configurations and 20 for the Mercedes-Benz GLB-Class, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.
Drivetrain and class: the Mazda CX-30 is offered with 4-Wheel Drive, Front-Wheel Drive, the Mercedes-Benz GLB-Class with Front-Wheel Drive, All-Wheel Drive, 4-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Small Sport Utility Vehicle 4WD and Small Sport Utility Vehicle 4WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.
Tailpipe emissions: at their cleanest configurations the Mazda CX-30 emits 309 g/mile of CO2 versus 311 g/mile for the Mercedes-Benz GLB-Class. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.
CX-30 vs GLB-Class: common questions
Which is better on gas, the Mazda CX-30 or the Mercedes-Benz GLB-Class?
The Mazda CX-30 is the more efficient of the two: it reaches 29 mpg combined versus 28 mpg for the Mercedes-Benz GLB-Class, a 1 mpg advantage and costs about $600 less per year to fuel.
Which costs less to run per year?
By EPA estimates at 15,000 miles a year, the Mazda CX-30 runs about $2,100 a year in fuel at its most efficient configuration, versus about $2,700 for the Mercedes-Benz GLB-Class — a difference of roughly $600 per year.
What engines do the CX-30 and GLB-Class offer?
Mazda CX-30: SIDI, SIDI; With Cylinder Deactivation. Mercedes-Benz GLB-Class: SIDI; Mild Hybrid, SIDI.
Are they in the same vehicle class?
Yes — the EPA classifies both the Mazda CX-30 and the Mercedes-Benz GLB-Class as Small Sport Utility Vehicle 4WD, so they compete directly.
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Comparison id: mazda-cx-30-vs-mercedes-benz-glb-class