How do you know how long it’ll be?
I was, hrm, what was I doing. Participating, I think, in the “books I’ve written” meme (available here, if you want to read it) and someone asked me how I knew how long a book was going to be. (This question could’ve been put to me/us here, too, and I just can’t remember. But I thought it was a good one, so I’m addressing it!)
Your average SF/F novel that you pick up, not the ones that make you go “Damn! That’s a big book!”, but the average ones that are an inch or so thick, run anywhere from, say, 90,000 words up to around 135-150K. That’s (using Courier New 12pt font with 1″ margins, .3″ tabs, and 25pt exact spacing) 380-600 manuscript pages, which is quite a spread. How, indeed, do you know how long your book’s going to be?
Well, if you’re not under contract, you generally want to be aiming for about 100K, not 150K. (There are exceptions. There are *lots* of exceptions. But *generally*, publishers like 100K books better than 150K books, because you can put 4 100K books into a supermarket wire rack and only 3 150K books. And I’m talking about SF/F here, not mystery or romance or YA or thrillers or anything else.) So if it’s your first book, you’re *probably* better off aiming for 100K than 150K. This is a pretty decent rule of thumb, I think.
Me personally, my writing approach is by thirds: the first third of the book is setup, the second third (which often pushes through to the 3/4ths mark) is plot & character development, and then the final third is all hell breaking loose on our way to the climax. So for, say,the Walker Papers, which are 110K books, that means I’ve got about 36K per third. It does not work out that tidily. Ever. But it’s not a bad mental structure to approach it with.
There is almost always a point in any book where I have two *extremely* different panic attacks at the same time. One is: “Oh my GOD how am I ever going to get all this story into the wordcount space I have left?!” and the other is, “Oh my god there is no way I have enough story to reach the wordcount I’m supposed to deliver.”
This (for me) means everything is going according to plan, and the book will come out at the right length.

