How many inches are your biceps?

My boyfriend and I have a bet, if his biceps get to be 16 inches by the end of the week he gets to pick the gym I join. I'm sure he will accomplish it because he's stubborn. I asked him what he would do, pull-ups, push ups, curls etc. and he said no curls- they are vanity muscle. They make you look a lot bigger but don't make you as strong as other exercises. So I got to thinking what is the average bicep measurement in inches for men? Assuming its fit men and no one will take a measurement of 20 inches of fat
How many inches are your biceps?
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