Trunk comparison: BMW X5 vs VW Polo

Key Differences
In terms of cargo volume, the BMW X5 shows significantly larger length dimensions: with the seats folded down, the X5's trunk is 18.9 in (+35%) longer, and with the first row of seats upright, it is 15 in (+58%) longer than the VW Polo.
The trunk opening of the X5 offers more vertical space, being 4.3 in (+16%) higher, and the opening width of the X5 is also 6.7 in (+18%) larger.
In contrast, the VW Polo has a significantly greater depth from the loading edge to the trunk floor: this is 2.8 in (+700%) larger in the Polo than in the X5. The loading edge of the X5 is 3.5 in (+13%) higher above the ground.
The narrowest width in the trunk is 3.1 in (8%) larger in the X5, but this difference is below the 10% threshold and is therefore less relevant.
Impact on Usability
The longer cargo areas of the X5 mean that longer items (e.g., skis, furniture parts, long boxes) can be accommodated much more easily—both with folded and upright seats.
The greater opening height and width of the X5 make loading bulky or tall items easier because more height and width are available at the loading point. At the same time, the loading edge of the X5 is higher, which makes lifting heavy loads over the threshold more strenuous.
The Polo scores with a significantly greater depth between the loading edge and the trunk floor, meaning a lower floor. This creates more space under the loading edge for flat-lying or stackable cargo and can be advantageous when transporting low, bulky items.
Additionally, the loading edge of the Polo is lower than that of the X5, which facilitates sliding heavy loads in. However, the overall shorter length and smaller opening of the Polo restrict the transport of long or very bulky items more.
Conclusion: For transport tasks involving long or very bulky parts, the BMW X5 is clearly advantageous. For frequent loading and unloading of heavy or flat-lying cargo (with a lower loading edge and deeper floor), the VW Polo can be more practical but requires compromises in length and opening dimensions.