Trunk comparison: Audi Q3 vs Hyundai Kona

Key Differences
With the rear seats folded down, the usable cargo volume of both models is the same size. With the first row of seats upright, the Audi Q3 is 1.6 in (≈5%) longer than the Hyundai Kona, and the height of the trunk opening is identical.
The depth of the trunk (distance from loading edge to trunk floor) is 1.6 in (≈80%) greater in the Audi Q3 than in the Hyundai Kona. Other, smaller differences: the loading edge of the Q3 is 2.8 in (≈10%) higher above the ground, the narrowest width in the trunk is 1.6 in (≈4%) larger in the Kona, and the width of the trunk opening is 3.1 in (≈8%) larger in the Q3.
Impact on Usability
The significantly greater depth in the Q3 means more vertical space below the loading edge — practical for transporting taller items in the cargo area and stacking boxes. The additional support volume can make loading bulky, tall cargo easier.
On the other hand, the loading edge of the Q3 is slightly higher; this makes lifting heavy items during loading more strenuous (minor effect, since there is only about a 10% difference here).
The wider trunk opening of the Q3 facilitates inserting wider items through the opening, while the Kona offers a bit more space at the narrowest point — relevant if an item fits through the outer opening but might get stuck at the narrowest spot inside.
Since the overall length with folded seats is the same, both vehicles are equally suitable for long items; with the rear seat upright, the Q3 offers slightly more depth.