Trunk comparison: Kia Sportage vs Tesla Model 3

Key Differences
The Tesla Model 3 offers a longer cargo space: It has a trunk that is 7.1 in (11%) longer with the seats folded down and 6.7 in (19%) longer with the first row of seats upright compared to the Kia Sportage. The trunk opening of the Kia Sportage is significantly higher (+8.3 in / 40%) than that of the Tesla Model 3. The depth of the trunk (loading edge to trunk floor) is 4.3 in (1000%) greater in the Tesla.
Smaller differences (under 10%) include: the loading edge of the Kia is 2 in (7%) higher above the ground, the narrowest trunk width in the Kia is 3.5 in (9%) larger, and the trunk opening width is 2 in (5%) larger in the Kia.
Impact on Usage
The longer loading length of the Tesla makes it more practical for long items (skis, slats, furniture boards) and offers more usable space when rear seats are folded down or heavy, long cargo needs to be loaded crosswise.
The significantly greater depth in the Tesla means more interior height below the loading edge, allowing larger or more stackable items to be stored more securely — at the same time, reaching and lifting heavy cargo further down into the trunk can be more demanding.
The higher trunk opening of the Kia facilitates loading bulky and tall items as well as handling during frequent loading and unloading (less bending, more pass-through height).
Despite slightly larger widths in the Kia, these differences are minor and noticeable only with particularly wide cargo. The somewhat higher loading edge in the Kia (7%) makes lifting heavy items slightly more strenuous.
In short: Those who often transport long or tall-stacked cargo benefit from the Tesla Model 3. Those who frequently load and unload bulky, tall items comfortably have advantages with the higher opening and slightly wider dimensions of the Kia Sportage.