How to get the real width of a button?

[SaltamonteZ]

Example:

var resetButton:Button = new Button();
resetButton.label = "Blabera Blub!";    
resetButton.move
(
   stage.width/2-resetButton.width/2,
   stage.height/2-resetButton.height/2
);
addChild(resetButton); 

Button always ends up slightly to the left.