Patty made a comment yesterday that prompted this post...thanks, Patty.
Let me start by saying that there is something that does remain a mystery to me, and that's how authors - some of them, anyway - seem to know exactly how long a book is going to be before they even start if. They plan it meticulously, plan what they are going to say and what the characters will do chapter by chapter, and lo and behold, then they finish it looks just as they thought it was going to. I am much more haphazard. I know the ending, but I have no idea how many words it will take me to get there.
When I say that the present book will be 180,000, I mean that's the aim. But we will see. I don't want to sacrifice story coherence, and I certainly don't want to pad, in order to reach that magical number. In fact, it isn't magical at all...it's just an estimation of how many words it will take to get this particular story written.
So how long should a book be, really, word-wise?
First of all, it depends on the genre.
Fantasy tends to be longer than Science fiction.
Historical fiction probably comes next in length, although sometimes it's up there with the fantasies...
Far behind, comes mainstream and Young Adult and other genres. Many - perhaps even most - of these are under 100,000 words. Why?
Basically, it's because with fantasy in particular, and to a lesser degree with historical and science fiction novels, the writer has to expend a large number of words telling the reader about the world. In a present day novel, you can say: Mary drove her dog to the vet's because it needed its shots, and in twelve words you have told the reader that we are talking about a woman who has access to a car and has a pet that she cares about. If the writer says, Illusa-zerise laid a hand on Korden's arm. 'He is your Mirager, Magori,' you have no idea of what is going on unless the world has been well-portrayed during the course of the story. (That's a sentence from Heart of the Mirage, by the way.) You don't even know if the people mentioned are male or female.
However, anything over 180,000 starts to get a bit unwieldy and presents publishers with a bigger cost. Unless they are very, very sure that you are a rising star in the publishing firmament, they are likely to tell you to cut down the verbiage. If you have already proved your self with your large sales figures they will smile happily because they know the reading public is going to be delighted to see a lengthy book from their favourite author.
Here are the approximate lengths of some of my books:
Havenstar (standalone and the first published book): 156,000
The Aware (first book in Isles of Glory trilogy) : 126,000
Gilfeather (second book) :146,000
The Heart of the Mirage (first book in Mirage Makers trilogy): 143,000
Song of the Shiver Barrens: 163,000 (Third book)
I can't remember the others, but I think they were in the 140-150,000 range. As you can see, I don't have a set number!
So what is the right length for an unpublished author?
The answer is:
1) Take a look at the length of the genre/type of book you are aiming to write, especially those written as first books.
2) Don't skimp and don't pad.
3) When you come to the end, if you think it is too skimpy, then consider rewriting scenes or characters at greater depth.
4) if you think it is too long, go through with your red pen. Look at unwieldy passages - can you say it more simply? Look at repetitions - especially of the kind where you show the action and then have characters discussing it, or worse, you the author pontificating on it.
Here's what agent Kristin on her entry for July 2nd had to say over at Pub Rants:
Some writers have an annoying habit of restating (via a thought their main character has) what has already been made apparent by the scene or the dialogue.
It's amazing how much you can tighten up your writing and improve your book, simply by cutting down on the unnecessary.
So what is the right length?
Answer: There is none. What counts is how good your story is, and how good your writing.
But for someone trying to break into the field, I'd be cautious about doing something too far outside the norm lengthwise.