These are some books that are well known and their word count...
The Catcher in the Rye by JD Salinger- 73,404
A Tale of Two Cities by Charles Dickens- 135,420
Fahrenheit 451 by Ray Bradbury- 46,118
Lord of the Flies by William Golding- 59,900
As you can see, books range from around 40,000 on average up to 150,000. I don't think that word count corresponds to whether the book is going to be good or not. I never thought that. Here's something interesting I found, The Harry Potter seres is a great example. The first book was a little over 76,000. After that they all went up in length. From 85,000 to 107,000 to 190,000 to 257,000 to 168,000 and the last book was 198,000. I found this pattern in many authors. Their debut book is always shorter than all their other books. Why is this?
Here is why. Publishers don't want to take a risk with your book. Your name is unknown and they aren't sure how the book is going to do. They would rather make more money on a shorter book. Of course once the book becomes known and if there is a positive response, the author gets more freedom.
Publishers actually have given out "recommend" word counts. Basically they won't accept anything less or more than what they ask for. Here is what I found on one website. Remember this is just for first time authors.
Adult fiction: 80,000-100,000 words.
Young Adult fiction: 40,000-60,000 words
Erotica novellas/short story collections: 40,000-60,000 words
Cozy mysteries only: 50,000-70,000 words
Most romance novels: 50,000-70,000 words
Short Story Collections: 40,000-75,000 words
Historical Fiction: 80,000-140,000 words
Adult Fantasy: 90,000-140,000 words
This is the real kicker. They actually put a disclaimer on the bottom of the page saying, "FYI: a 140,000 word debut novel is about as scary as Joan Rivers' face. So if you're shopping a 140K chubby moon-glop monster, you might want to consider NOT advertising this fact in your query letter" Basically they're saying if you have a long book don't publish it until you publish a shorter book first. That's crazy.
I consider writers to be artists. We have imaginations. We create art with our words. How can someone tell us that the book is too long before even reading it!? It's so crazy. Personally this research solidifies my mission to self publish. I can do whatever I want! I want artistic freedom. If someone told me my 100,000 book was too long (It's YA Fantasy) I don't know what I'd do. There is absolutely nothing I could just chop out of the book.
Anyway, I hope you enjoyed this post. It only made me mad! Don't give away your artistic freedom. Self publishing is easier than ever. Good luck!!