how to include padding in width code example

Example 1: border-box css

#example1 {
  box-sizing: border-box;
}

Example 2: stop padding from changing div size

-webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */
-moz-box-sizing: border-box;    /* Firefox, other Gecko */
box-sizing: border-box;         /* Opera/IE 8+ */