wp excerpt lenght limit

functions.php

function excerpt($limit) {
    $excerpt = explode(' ', get_the_excerpt(), $limit);
    if (count($excerpt)>=$limit) {
        array_pop($excerpt);
        $excerpt = implode(" ",$excerpt).'...';
    } else {
        $excerpt = implode(" ",$excerpt);
    }
    $excerpt = preg_replace('`\[[^\]]*\]`','',$excerpt);
    return $excerpt;
}

//source: http://smallenvelop.com/4-ways-to-limit-post-excerpt-length-in-wordpress/