Figuring gage

I saw a book by jackie fee and sweaters that had a calculation page in it for refiguring the gage of anything that you are working on, its more like you are making a new garment, i was wondering since i dont have the book, if anyone has that formula it is alot of figurering but we want to knit a sweater and are really worried about gageing if anyone can help out there that would be great


Do any of these help you?

Although that one has pages for other clothing items as well: