Depends on how you want it to ride really. There really is no correct size, only recommended size by the manufacturer based on how the board is intended to ride.
Lots of factors to consider here, What are you looking for in this board? Is it your only board? Are you a beginner? Advanced? Size shoe? Weight? Provide those and you'll give more experienced members on here something to work with. I'm sure the size suggestions will start rolling in shortly after that.