Trunk comparison: Audi A3 Sportback vs Fiat Panda

Key Differences
The Audi A3 Sportback offers significantly more space lengthwise: with the seats folded down, the trunk is 15 in (34%) longer, and with the first row of seats upright, it is 9.1 in (43%) longer than the Fiat Panda.
In contrast, the Fiat Panda has advantages in the vertical dimension: the trunk opening is 4.3 in (14%) higher and the depth from the loading edge level to the trunk floor is 0.8 in (13%) greater than in the Audi.
Impact on Usability
The longer cargo areas of the A3 clearly make it superior for long items and flat-stored cargo — such as furniture parts, long sports equipment (skis, snowboards), or long boxes. Those who regularly transport bulky, lengthwise-oriented goods or need more usable cargo space with folded seats will benefit from the A3.
The Fiat Panda is better suited for bulky, rather tall or stackable cargo: The higher trunk opening makes it easier to load tall items and bulky boxes that are stored vertically. The greater depth to the trunk floor offers a bit more usable height and room for stacking or placing items below the loading edge.
Other differences, such as the slightly higher loading edge on the Panda (+0.8 in / 3%) and the marginally greater width at the narrowest point and the opening (+2–1.2 in / 2–3%), are minor and only marginally affect practical use: they slightly improve handling of smaller, wider items but do not change the fundamental usage style of the two models.