Date::Calc (or, heaven forbid, Date::Manip) is probably overkill since you only want age in years. All you really want to know is whether the birthday has passed this year. 
sub age {
    # Assuming $birth_month is 0..11
    my ($birth_day, $birth_month, $birth_year) = @_;

    my ($day, $month, $year) = (localtime)[3..5];
    $year += 1900;

    my $age = $year - $birth_year;
    $age-- unless sprintf("%02d%02d", $month, $day)
               >= sprintf("%02d%02d", $birth_month, $birth_day);
    return $age;
}

[download]
Of course, if you're only using this on a person's birthday, all you need to do is subtract their birth year from the current year :-)

In reply to RE: RE: Re: Calculating a persons age based on their birthday. by takshaka
in thread Calculating a persons age based on their birthday. by artful

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.