How long does it normally take a stone in the mid pole to pass into the ureter?

Unpredictable...: It is unpredictable to tell when a stone attached to a calyceal papilla may drop and move into the ureter so hopefully pass through ureter into the bladder; so, no one can tell, but just be alert for such occurrence as described. In general, the odd for a 4-mm stone to successfully pass is about 75-85% in 2 weeks, but it does not mean a stone < 4 mm will not pass or one >4 mm will never pass.