icon font doesn't fit to center in big size

Question

I'm using fonttello, but it doesn't scale from center.

my html

<span class="icon-marker-dot x2 icon_centering"></span>

css

.icon_centering {
    font-size: 5.5em;
    color: #FFF;
    background: #428bca;
    border-radius: 50%;
    display: inline-block;
    text-align: center;
    width: auto;
    height: auto;
}

Answer 1

FIDDLE, now the whole thing will scale when you change the font-size

CSS

.icon_centering {
    font-size: 5.5em;
    line-height:2.5em;
    height:2em;
    width:2em;
    vertical-align:middle;
    overflow:hidden;
    color: #FFF;
    background: #428bca;
    border-radius: 9999em;
    display: inline-block;
    text-align: center;
}