botón Bootstrap Circle
<button type="button" class="btn btn-info btn-circle">
<i class="glyphicon glyphicon-ok"></i>
</button>
Azizul7m
<button type="button" class="btn btn-info btn-circle">
<i class="glyphicon glyphicon-ok"></i>
</button>.btn {
display:block;
height: 300px;
width: 300px;
border-radius: 50%;
border: 1px solid red;
} <button type="button" class="btn btn-primary btn-circle btn-sm">Blue</button>