as TxAg mentioned above there are allot of variables...
I draw a tad over 27"s my Son-in-law draws an honest 30+ inches....
Here's a monkey wrench
I am 6' tall and a size 48 my Son-in-law is 6' maybe a size 44/45.... When we stand back to back I have a solid 3"s of tip to tip arm length and I am wider in the shoulders.... I anchor with my pointer finger in the corner of my mouth he anchors with the pointer at the jaw maybe two inches from the corner of his mouth... my stance is more open than his and nether of us cant a bow much... he is 34 yrs old I am 59 (I mention this because I think my shoulders compress more at full draw now than when I was younger) .... I am taller and wider in the shoulders than him and even with his 2" longer anchor spot the math don't add up. I should have the longer draw on paper
Have you got a headache yet