Trunk comparison: Audi A4 Avant vs Mercedes Benz GLB

Key Differences (>10%)

The Audi A4 Avant offers with the rear seats upright a cargo floor that is 3.9 in or 11% longer than the Mercedes‑GLB. Two features stand out in the GLB: the trunk depth (loading edge to trunk floor) is 2.8 in or 140% greater and the loading edge is 3.5 in or 14% higher above the road than in the A4.

Impact on Usability

Cargo lengthwise: Due to the 11% greater length with the rear seats upright, the A4 Avant is better suited for long items (e.g., skis, long boxes, slats) that need to be transported without folding down the rear seats.

Lifting and gripping: The 14% higher loading edge of the GLB means that heavy or bulky loads must be lifted higher when loading — this often makes frequent loading/unloading more difficult compared to the A4.

Vertical capacity and interior shape: The significantly greater depth (140% more) in the GLB creates a lower cargo floor below the loading edge.

This increases usable vertical capacity for bulky or tall items but can make inserting heavy, flat items more difficult (more effort to lift over the higher loading edge) and may require reaching for items placed far back.

Secondary values (smaller differences): The GLB has only a few percent more at the narrowest point and in opening width — this provides slight advantages when loading wide items but is not a decisive factor for most everyday scenarios. The height of the trunk opening is also slightly higher in the GLB (+4%).

Conclusion: Those who frequently transport long items benefit more from the Audi A4 Avant. Those who benefit from a lower cargo floor and somewhat more vertical capacity as well as a slightly wider opening (and accept the higher lifting) are better off with the Mercedes‑GLB.