Average book page for me this year is above 400 pages according to Goodreads. I read fantasy and 90% of that genre are big books around 700 and above. But with occasional science fiction that number dropped in my stats.
I don't read self-published works, but imo, in fantasy at least you need 500-600 pages to really develop the characters and do some solid world building. This is especially true for epic fantasy I think. In urban fantasy, things are usually faster paced so you don't need that much and series are longer, they are not usually trilogies as is the case with epic so you have more books to do the same.
That being said, there's a lot of fluffing and buffing in fantasy, because there is a certain expectation by the publishers. So you do get a lot of books that could have been shorter, that have a simple story line, but are nonetheless inflated to 700 pages.
|