Suzeeq, you are so funny! I lost you right after you said Easy way!
LovelyLinda-I think I am wanting it to be fairly flat against the window, it is going to go on our back door so it will be moving quite a bit. I don't want to to be much bigger than the window width as I don't want to always have to open the door to get the curtain out of the door.
Jan in CA-I think I am going to try casting on 160 stitches and knit a few rows and see how it fits.
Thank you all for trying to help me in my bad math brain. My husband on the other hand works with numbers all the time and just about breathes them!