The following code shows how to layout well inside span6.
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='/js/lib/mootools-core-1.4.5-nocompat.js'></script>
<link rel="stylesheet" type="text/css"
href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.1.1/css/bootstrap-combined.min.css">
<style type='text/css'>
.descrCounter, .sparetimeCounter {<!--from ww w. jav a 2 s. c o m-->
font-weight: bold;
}
.counterRight {
border: 1px solid red;
}
</style>
</head>
<body>
<div class="container">
<div class="row-fluid show-grid">
<div class="span6 counterLeft well">
<span class="descrCounter">190</span> Characters left
</div>
<div class="span6 counterRight well">
<span class="sparetimeCounter">185</span> Characters left
</div>
</div>
</div>
</body>
</html>