Trunk comparison: Audi A4 Avant vs Kia Ceed

Key Differences (>10%)
The Audi A4 Avant offers a 11.4 in (19%) longer trunk with the rear seats folded down and a 10.2 in (33%) longer cargo space with the front seats upright compared to the Kia Ceed.
The trunk opening of the Audi is also 3.9 in (13%) higher. In contrast, the trunk depth of the Kia Ceed (distance from loading edge → trunk floor) is 2.4 in (120%) greater than that of the Audi.
Impact on Usability
The significantly greater cargo length in the Audi makes it overall more practical for long items (skis, boards, furniture parts) and for situations where the rear seat is frequently folded down (moving, longer cargo pieces).
The higher trunk opening of the Audi facilitates loading tall or bulky items because more clearance height is available.
The greater depth value of the Kia (loading edge → floor) affects handling when loading: in practice, this means the interior floor lies relatively further "below" the loading edge.
This can result in heavy items needing to be set down lower and the rear interior being deeper — advantageous when preferring flat-stacked cargo but disadvantageous when frequently loading bulky, long items or filling the trunk up to the opening.
Additionally, the loading edge of the Kia is slightly higher (+1.2 in, 5%), making lifting heavy loads somewhat more strenuous (difference under 10% but practically minor).
Width and opening width differ only minimally (narrowest width: Kia +1.6 in / 4%; Audi opening width +0.8 in / 2%) and therefore have hardly noticeable effects on everyday usability.
Conclusion: Those who often transport long or tall items and need flexibility in folding down the rear seats benefit more from the Audi A4 Avant.
The Kia Ceed offers advantages in flat stacking due to the deeper loading floor and feels more compact but is clearly at a disadvantage in length and pass-through capability.