TIL – A work of fiction between 20,000 and 49,999 words is considered a novella. Once a book hits the 50,000 word mark, it is generally considered a novel.

Read more: https://www.authorlearningcenter.com/writing/fiction/w/identifying-your-genre/7125/short-fiction-forms-novella-novelette-short-story-and-flash-fiction-defined#:~:text=A%20work%20of%20fiction%20between,is%20generally%20considered%20a%20novel.