I have mentioned previously that the ideal length for a manuscript is between 80,000 and 100,000 words, but as your questions have highlighted, there is often a bit more to it than that...The word length for a manuscript is not set in stone, but here are some general guidelines that are well worth bearing in mind as you write, and of course later as you submit.
Think of a paperback that you own which is between 300 and 400 pages: this is the typical paperback novel and it's almost certainly 80,000 to 100,000 words long.
But, here are some of the common variations you might encounter:
- a literary novel can often weigh in as shorter, say 60,000 to 80,000 words
- a 'blockbuster' can be longer, as can a sci-fi or historical fiction novel. (Crime tends to stay within the typical length.)
- a children's book is normally shorter and a picture book (being mainly illustration based) can be as little as 100 words
- a children's novel for 5- to 8-year-olds is likely to be around 20,000 words
- Once you are writing for the 8- to 12-year market, I would aim for around 40,000 words. (Teen or cross-over fiction comes in at adult fiction lengths.)
Why does amy of this matter? And surely if you have written a masterpiece, the publisher should accept the length as it is? Well maybe. Publishers are driven in equal measures by commercial and creative impulses. They will still consider the odd anomaly - but you are then having to persuade them that much more that your work is worth taking on.
Why make it harder for yourself? Working within a length framework gives you structure, and also a guide as to how much time you have to develop a plot, and introduce characters.
Good luck!
Cressida
(editorial consultant)

Danny Coyle on November 12, 2009
This is a worry of mine concerning the book I am currently working on. Each of the first ten chapters is coming in at lengths varying between 1000 and 2,500 words. What happens if I come to the end and only have 40,000 words in total - is this too short for any agent or publisher to bother with?
Paul Lamb on November 14, 2009
Sorry, but I have some trouble with this. It seems to me that you must write the story you have, as well as you can, and finish only when it is done, not when some more marketable word count is achieved.
Toxicparadox@live.co.uk Popplewell on November 16, 2009
This terrifies me, but at the same time I think it's better to have something to aim for. The first draft of my manuscript has ended up being 30,000 words - I know that's more or less a novella, but rather than being discouraged it has given me an opportunity to think about what is missing from my story; what other elements can I add? Can I explore the relationships between characters further? Can I create more of a world around my plot?
As a second year university student, I shouldn't be spending so much time on my manuscript, particularly as my Creative Writing tutor was incredibly scathing about my first chapter, but I'm learning, and writing as I learn.
Danny Coyle on November 16, 2009
Well, I have to say that I'm encouraged by these responses. Onward, then, to the end, wherever that may eventually be!
Cressida Downing on November 18, 2009
TR1980 - there are no guidelines when it comes to chapter length, except that it's worth remembering that the average paperback book will fit in 350-400 words on a page. If your chapter is 1,000 words long, it will only go over 2 and a half pages, so it may be what you are writing aren't chapters as such - but more where your narrative takes a natural break.
Paul Lamb - I absolutely agree with you, you must write as you feel it - not to marketing rules, but it is worth knowing what the industry expects, should you wish to take it further, and try for publication.
Publishers will accept books that are outside of these guidelines, but they will have to find them exceptional to take them forward. A good novel that is too long might be rejected under those circumstances because the editor cannot justify the length.
ToxicParadox - you raise a good point. The suggested lengths aren't arbitrary, they are what the reader has come to expect will encompass all the elements of a good novel, explored at a length that 'feels' right. Sometimes you begin to write a novel, and realise it's a short story, or vice versa.
Good luck with all your projects,
Cressida