Although tending to length isn’t critical while drafting a novel, I decided I wanted some parameters … that I might as well try to keep my manuscript within the realm of acceptable length all along rather than over-write now and need to seriously prune later.
So I researched publishers and gathered their preferred word-count ranges. Then I opened some of my favorite novels and estimated their word counts: the general number of words per line, multiplied by the number of lines per page, multiplied by number of pages in the book. For novels I don’t own but which are similar to the one I’m drafting, I planned to go to Amazon.com, where I’d view a page of the book and proceed as above. In the process, I stumbled upon a cool feature.
For some (Amazon says all) of the books with the “Search Inside!” feature, Amazon now provides text statistics, including word count. Simply select a book and scroll down the page past the Editorial Reviews and past the Product Details to the Inside This Book space. In the New! section, click on Text Stats. I’d estimated 60,000 words for Harriet the Spy, my favorite middle-grade (ages 9-12) novel; Amazon says 57,959.
You can compare the word count (and the book’s readability statistics) to other books -- by default, the comparison is against all others; click the arrow to target it to related titles, e.g. other books for children aged 9-12. Harriet the Spy is a slightly easier read than other middle-grade books, but much longer. And though it still sells today, it was first published in 1964; it will be important to consider the lengths of recently published novels.
[As to the absurdity of Amazon’s Text Stats, read this and this.]