Assuming you are wearing a dress shirt untucked... how long should it be in inches below the waist? Of course its suppose to be tucked in but if not untucked... how many inches? I heard 7' was good. The reason why i ask this is because i wore a dress shirt and i thought it was way too big because it was too long below my waist. The fitting was fine but it was just so long from top to bottom. Depending on the shirt, this is pretty flexible. It can range from a few inches below the belt, to just above where the crotch ends and the pant leg begins. I think that it starts looking sloppy if it goes past the crotch. With untucked shirts be careful to make sure that the shirt is slim enough that it doesn't seem drapey. Also make sure that it's long enough on the sides such that you can move naturally without displaying an undershirt. You can get away with a shirt that's a little longer if you're wearing a sweater. Google untucked shirts and just go with the look that you like.