JK Rowling pens a Harry Potter prequel

[Carol]

Carol earlier:
> > 
> > Sorry to disappoint you, kemper. It's an 800-page short story about
> > the Marauders that takes place three years before Harry's birth.
> 
> Potioncat:
> JKR would consider 800 pages to be a short story.
> ;-)
>
Carol responds:

Did I say 800 pages? I meant 800 words!

Carol, who counts 250 words as one 8 1/2-by 11-inch page in her
editing projects, so it would be a 3.2-page short story (maybe three
pages on A4 paper?)