Edit in JSFiddle

jQuery(function($){
	$('.to_center').each(function(){
		var new_width = 0;
		$(this).children('.floated').each(function(){
			new_width += $(this).width();
		});
		$(this).width(new_width);
	});
});

<div class="to_center">
  <div class="floated">floated text</div>
  <div class="floated">floated text</div>
  <div class="floated">floated text</div>
</div>

.to_center {
  margin-left: auto;
  margin-right: auto;
}

.floated {
  float: left;
  background-color: lightyellow;
}