Single Status Update
Is there an official case size cutoff for what is and isn't an SFF case?
The next largest case type, the mini-tower, is usually defined as a case that stands 12" - 18" tall. We could probably label cases that are shorter than 12" - 18" as SFFs? I couldn't find an exact size or volume cutoff for SFF cases, however. The general consensus seems to be a wishy-washy, "SFFs are smol."Spoiler
Sources: Small Form Factor Buyers’ Guide by Anandtech, Types of Computer Cases and Motherboard Form Factors by Utilize Windows, Small Form Factor and Computer Case on Wikipedia.
we've generally accepted intel's definition (surprise! i lost the link to the old pdf though ,_,) of 20L and smaller (20 x 1,000,000 cubic millimeter or 1,000 cubic centimeter), but SFF purists and extreme enthusiasts tend to prefer going lower than 10L
it's less strict for contemporary discussion, but cases that only mount ITX boards would be held to the standard more closely, especially if an ATX motherboard could float in there
there is a separate but somewhat parallel school of thought called Space Efficiency, where a case would have very little empty space when loaded, all while not impeding airflow and thermal performance. SFF cases tend to easily check that aspect, but specific cases above 20L could also be space efficient (e.g.: servers)
either way, if you can't do this to your build for more than 10 minutes, it's unlikely that people would regard it as SFF