Trunk comparison: BMW X4 vs Fiat Panda

Key Differences
The BMW X4 offers significantly more cargo length: with the seats folded down, the trunk is 24 in (55%) longer and with the front seats upright, 18.9 in (89%) longer than the Fiat Panda. This makes the X4 clearly more advantageous in lengthwise cargo space.
The Fiat Panda, on the other hand, has a higher trunk opening and a deeper loading area: the opening height is 7.1 in (26%) greater and the distance from the loading edge to the trunk floor is 3.9 in (125%) greater than the X4. Additionally, the loading edge of the BMW X4 is 3.9 in (14%) higher above the ground than the Panda.
Impact on Usability
Longer loading surface (BMW X4): The significantly greater loading length of the X4 makes it better suited for long items such as slats, pipes, skis, or flat furniture parts. Even with seats folded up or partially folded, longer cargo can be accommodated more easily in the X4.
Higher opening and deeper loading area (Fiat Panda): The higher opening of the Panda facilitates loading bulky, tall items in an upright position (e.g., boxes, plants). The greater depth between the loading edge and trunk floor provides more vertical storage space and allows for deeper stacking.
Lower loading edge in the Panda vs. higher in the X4: Because the Panda’s loading edge is lower, lifting heavy items into the vehicle is easier and more ergonomic. The higher loading edge of the X4 means more effort is required when stowing heavy loads and increases the risk of bumping things.
Width differences: Differences at the narrowest point (+0.4 in in the Panda) and at the opening width (+1.2 in in the X4) are small (<10%) and have little practical impact on usability.
Conclusion
For transporting long items and larger cargo lengths, the BMW X4 is clearly superior.
For everyday use involving frequent loading of heavy or tall items (groceries, plants, boxes) and easier physical loading and unloading, the Fiat Panda is more practical due to its higher opening, greater vertical loading depth, and lower loading edge.