I’m working on a YA novel. As I understand it, such novels should be about 150-200 pages in length when they’re printed. I’m composing in 12pt. Times New Roman in WordPerfect, and rather than risk being wrong about how many pages of that would correspond to 150 typeset pages, I’d like to measure it in words. So how many should I have? Thanks in advance!
You would definitely be wrong if you went by page count. Always work by word count.
Off the top of my head 40 000 words is pretty standard for YA. Have you considered publishers yet? It might be a good idea to start requesting guidelines. Some publishers are more flexible than others. I know that Scholastic FE tend to be rigid around word count.
Believe it or not, many, if not most publishers still prefer to have manuscripts submitted in non-proportional fonts. Courier or Courier New are still the best fonts for manuscripts. My version of WordPerfect has both.
Duly noted. Thank you!
And as a college sophmore I can assure you Courier New will get you anywhere from a 20 to a 40% increase in length. 
Ahh, Courier New, the best friend of THIS college student.
“Hmm, only 7 pages. click click Hmm, 13! That’s better!”
Increasing the length of your manuscript as opposed to your essay is not necessarily a good thing.
We work in Times New Roman and every publisher I’ve ever had anything to do with uses Times New Roman too. But then we don’t want to inflate word count or length generally. Exapno’s mileage obviously differs so I’d check with a publisher before I used any font.
It’s not a matter of stretching it out to as many words as I can. If anything, an editor will probably tell me to be a lot more concise, and leave out a scene or two. I’m writing it to be as long as I feel it needs to be, while preparing to sacrifice what an editor feels should be sacrificed.
It’s easier to cut than to expand. Plus I fear that if I submit something that’s way short, the response will be along the lines of “You barely squeezed this out, eh?..Guess you don’t have much more in you.” I have a lot more in me, so if an editor says “This bit has to go”, I’ll leave it out, and perhaps work it into a later installment. They’re the ones who know what sells.