Trunk comparison: Audi Q3 vs Tesla Model Y

Key Differences
In terms of cargo space, the Tesla Model Y offers significantly more length: with the seats folded down, the trunk is 11 in (+17%) longer, and with the first row upright, it is 8.3 in (+23%) longer than the Audi Q3. Conversely, the Audi Q3 has more space in several aspects of the loading and build geometry: the height of the trunk opening is 3.5 in (+13%) higher, the depth (loading edge to trunk floor) is 3.5 in (+800%) greater, and the width of the trunk opening is 4.3 in (+11%) wider than the Tesla.
Smaller differences (e.g., loading edge height +2 in / +7% and narrowest trunk width +2 in / +5% in favor of the Audi) exist but are below the 10% threshold and less significant.
Impact on Usability
The greater length dimensions of the Model Y make it easier in practice to transport long items (e.g., skis, long furniture parts, dimensional lumber). Those who frequently load long cargo or regularly load with folded seats benefit from the Tesla due to significantly more cargo length.
The Audi Q3, on the other hand, scores when carrying bulky, wide, or tall items: the higher trunk opening and larger opening width make loading and unloading bulky items easier and provide more room for maneuvering large boxes or luggage.
The significantly greater depth (loading edge → floor) indicates a deeper cargo area, which additionally creates storage space below the loading edge — this can mean more usable volume but also makes lifting heavy items from the depth less comfortable.
Practical short recommendation: If you often transport long items or prefer a low loading edge, the Tesla Model Y is more advantageous. If you more often have wide or tall, bulky cargo and benefit from a larger opening and deeper cargo area, the Audi Q3 is better suited.