Math challenged!

Please forgive me if this question has been asked before, but I just can’t seem to understand my yardage requirements for sweaters. I know they are often given with each pattern, but I often change the pattern {make it longer, add on a hood, etc}I do know that if my yarn gives me a gauge of 4 stitches per inch, I generally require roughly 2200 yards to make what I want. Now if I get a yarn that gives me say, 3 stitches per inch, my yardage should be less, right?? If so, how much less yardage would I need? Would the knitting software programs help in yardage estimation? I ask because often I come across some delightful yarn at my lys, but am often unsure just how much of it to get. It wouldn’t be a problem to get more than I need, but unfortunately my tastes run towards the more expensive yarns! :cry: What I’m specifically thinking of is Noro’s Iro. I have just fallen in love with this yarn, but to purchase enough to make a sweater, I would have to take out a bank loan! 2200 yards of Iro is a small fortune, so can anybody help? Oh, and thanks!:muah:

You can get a " Knitter’s Handy Guide to Yarn Requirements" and never have to ask that question again. It fits in the pocketbook and has all the info for mittens, hats, gloves,socks, sweaters, vests and more. I may be a math wizard but this makes it easy for me and I don’t have to waste time doing calculations when buying yarn.
I could answer that question but chest/bust size is necessay for the correct answer. According to my chart for bust size of 54 inches you would need 1866 yards, 4 stitches to the inch. For three stitches to the inch you would need 1315 yards.
You might be able to find this kind of chart online but I got the guide and it costs only 3 dollars. I take it to the yarn shop where ever I go.
I hope this helps.:thumbsup:

Thank you so much! Did you get this at your lys?

Yes,:drool: I did get it at my lys but you can get it at JoAnns Fabrics or at least I saw it in my JoAnns.

Thank you much!