Getting the time difference from two different days using date function

$startTime = "2011-01-10 12:10:46";
$endTime = "2011-03-15 10:39:09";

$timeDiff = floor((strtotime($endTime) - strtotime($startTime))/(60));
$timeStandard = ($timeDiff == 1)?"Minute":"Minutes";
if($timeDiff >= 60)
{
    $timeDiff = floor($timeDiff/60);
    $timeStandard = ($timeDiff == 1)?"Hour":"Hours";
   
    if($timeDiff >= 24)
    {
        $timeDiff = floor($timeDiff / 24);
         $timeStandard = ($timeDiff == 1)?"Day":"Days";
       
        if($timeDiff >= 7)
        {
            $timeDiff = floor($timeDiff / 7);
             $timeStandard = ($timeDiff == 1)?"Week":"Weeks";
           
            if($timeDiff >= 4)
            {
                $timeDiff = floor($timeDiff / 4);
                 $timeStandard = ($timeDiff == 1)?"Month":"Months";
            }
           
        }
    }
}

echo $timeDiff." ".$timeStandard;