Trunk comparison: BMW X4 vs Kia Stonic

Key Differences

Two clear strengths stand out in the cargo space: The BMW X4 offers significantly more length. Specifically, the X4 has a trunk that is 13.8 in (26%) longer with the seats folded down and even 13 in (48%) longer with the first row of seats upright compared to the Kia Stonic.

On the other hand, the Kia Stonic leads in vertical dimensions: The height of the trunk opening is 3.5 in (13%) greater in the Stonic, and the depth from the loading edge to the trunk floor is 3.9 in (125%) higher than in the X4. All other differences (widths and loading edge height) are in the single-digit percentage range and thus significantly smaller.

Impact on Usability

The greater length capacity of the BMW X4 makes it more practical for long or flat items like skis, slats, long boxes, or furniture parts. Those who frequently transport bulky, elongated loads or regularly fold down the rear seats clearly benefit from the X4.

The Kia Stonic, on the other hand, has an advantage in handling tall and low-sitting cargo. The larger opening height makes loading tall items (e.g., boxes or suitcases that need to stand upright) easier.

The significantly greater depth from the loading edge to the trunk floor also means a deeper cargo area—this can offer more volume for loose or stackable items, and makes lifting very heavy loads over the loading edge somewhat easier because the loading edge is overall a bit lower.

For users who often transport tall or bulky but not necessarily very long items, the Stonic is more practical.

Conclusion: Those who need elongated cargo and maximum usable length should choose the BMW X4. Those who often load tall or bulky, relatively compact cargo and benefit from a higher opening are better off with the Kia Stonic.