How does the roster limit work with draft picks?

I know we have a 50 player roster limit. With 12 picks in the upcoming draft so far, that'll be 12 additional players for us. Wouldn't that put us at 62? Is there a perfect balance of players going out as there are players coming in or are draft pick prospects not included in the 50 player limit? And if that's the case at what point are they included in the 50 player limit?