There is no set standard. On average, the border of a short film runs at 30 minutes, then, from 30 to 60 minutes — a medium-length movie, more than 60 minutes — a feature one.
At the same time in different short films festivals the borders can be even 10 or 45 minutes. The most common are 15 and 30 minutes. At American film festivals the practice of certain border between a short and a full meter is accepted — 50 minutes. Anything shorter is considered a short film; anything that is longer is feature one. At the same time, films of average length, even if they fit into the rules of the festival, are difficult toset in a festival program.
There are even special festivals focused on medium-length cinema, but there are few of them, therefore, in terms of promotion, such films are the most difficult to work with.
Short films from 20 to 30 minutes can also be difficult to fit into the program, especially at festivals with a small competition, where the number of sessions is limited. There is also a microfilm format, usually up to 3 or 5 minutes.
There are festivals that are focused on this format, and it is also distributed in special competitions, where a narrow theme is set.