<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container">
<div class="row">
<div class="col-lg-5">
<h2>All size buttons</h2>
<p>Add a class .btn-* to set the size of button.</p>
<a class="btn btn-xs btn-default">.btn-xs</a>
<a class="btn btn-sm btn-default">.btn-sm</a>
<a class="btn btn-default">default</a>
<a class="btn btn-lg btn-default">.btn-lg</a>
<a class="btn btn-xl btn-default">.btn-xl</a>
</div>
<div class="col-lg-7">
<h2>All Size rounded buttons</h2>
<p>Add a .btn-round class to round as button sides<small> (The same button as above)</small>.</p>
<a class="btn btn-round btn-xs btn-default">.btn-xs</a>
<a class="btn btn-round btn-sm btn-default">.btn-sm</a>
<a class="btn btn-round btn-default">default</a>
<a class="btn btn-round btn-lg btn-default">.btn-lg</a>
<a class="btn btn-round btn-xl btn-default">.btn-xl</a>
</div>
</div>
<hr>
<div class="row">
<div class="col-lg-12">
<h2>Button Groups - Set Sizes</h2>
<p>To form a group of buttons add the class .btn-group-* into a div with the buttons.**</p>
<p><small>* - Replace with the size of the buttons xs, sm, lg or xl (xl is a size class of this snipped).</small></p>
<p><small>** - For the default size use .byn-group</small></p>