Trunk comparison: Audi A3 Sportback vs Audi A4 Avant

Main Differences

The Audi A4 Avant offers significantly more cargo space in length: With the seats folded down, the trunk of the A4 is 13.4 in (23%) longer, and with the first row of seats upright, it is even 11 in (36%) larger than the A3 Sportback. The Audi A3 Sportback, on the other hand, has a significantly deeper trunk well: The depth from the loading edge to the trunk floor is 4.3 in (220%) higher in the A3 than in the A4. The other dimensions differ only slightly: The trunk opening of the A4 is 2 in (5%) wider, the opening height of the A4 is 3.1 in (10%) higher, and the loading edge of the A3 is 1.6 in (6%) higher above the road; the narrowest interior width is the same in both models.

Implications for Usability

The significantly greater loading length of the A4 Avant makes it more practical for long items (e.g., slats, long skis, bulky furniture parts) and for more volume with travel luggage, especially when the rear seat is folded down.

The greater loading length also improves flexibility when loading items of different lengths.

The deeper trunk well of the A3 means that items can be "sunk" further into the trunk — this can be useful when transporting smaller, higher-stacked items or for concealed storage.

At the same time, the deeper well combined with a slightly higher loading edge above the road results in a greater lift when loading and unloading heavy items, which can make handling more difficult.

In summary: For transport tasks requiring length and volume, the A4 Avant is the better choice. For cases where a deeper well (e.g., for hiding or stacking luggage) is advantageous, the A3 Sportback offers strengths — albeit at the cost of greater effort when lifting heavy loads.