$re = '/^(0?[1-9]{1}|[1]{1}[0-7]{1})(\s|[-])?(y(\s?)o|yr([sz]?)|year([sz]?)((\s|[-])?(old)?)|y)((\s?|[-])(old)?)$/m';
$str = '10y
10yr
10yrz
10yrs
10 y
10 yr
10 yo
13 y o
09y
9y
09 y
9yr
9yo
9year
9 years old
9 yearz old
17 yo
17year
17 years
17 yearz
17-year-old
100years
13
10 your
18 yr
18yr
10 your
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php