How to add badge on top of Font Awesome symbol?

Question

I would like to add badge with some number (5, 10, 100) on top of the Font Awesome symbol (fa-envelope). For example:

Answer 1

While @Paulie_D's answer is good, it doesn't work so well when you have a variable width container.

This solution works a lot better for that: http://codepen.io/johnstuif/pen/pvLgYp

HTML:

CSS:

.fa-stack[data-count]:after{
  position:absolute;
  right:0%;
  top:1%;
  content: attr(data-count);
  font-size:30%;
  padding:.6em;
  border-radius:999px;
  line-height:.75em;
  color: white;
  background:rgba(255,0,0,.85);
  text-align:center;
  min-width:2em;
  font-weight:bold;
}