That all depends...Are you playing a cash game or a tournament.
If a cash game then the chips should equal whatever the buyin is, if a tournament then you could do damn near anything you want. The deeper the stacks the longer it will likely take. 100 times the big blind is a place to start but you could easily go more or if you really want less. I would also ensure you have a timer for the blinds if you are playing tournament style to keep the game on track. Good Luck.