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.