Yes, collar. I usually wear 18 - 36. But, it seems like in some of the higher end shirts they were a little more slim fitting, so I need a little more room which is why I said 18.5. Plus, i think sometimes the used ones might have shrunk a little. It does need to be a longer sleeve/longer shirt. I got a few shirts from folks on here that were great shirts and fit, but they were too short.