user age from mktime()

[Tewl]

I use mktime to save a users birthdate:

$birthdate = mktime( 0, 0, 0, $month, $day, $year);

Can someone show me how I would get the users age from this.

[intenz]

$age = mktime(0,0,0,12,13,1985);
echo date('Y') - date('Y',$age);
// Output: 17

[barand]

As unix timestamp starts at 1970, it will not calc ages over 32

function age($d,$m,$y) {
  $ydiff = 1970 - $y;
  $bd = mktime(0,0,0,$m,$d,1970);
  return $ydiff + date("Y") - date("Y",$bd);
} 

echo age(13,12,1985)."<br>"; // = 17
echo age(22,1,1949)."<br>"; // = 53

[barand]

Or, more accurately, taking the month and days into account

function age($d,$m,$y) {
  $ydiff = 1969 - $y;
  $bd = mktime(0,0,0,$m,$d,1970);
  $bdarray = getdate($bd);
  $nowarray = getdate(time());
  if ($bdarray["yday"] < $nowarray["yday"]) $ydiff++;
  return $ydiff + date("Y") - date("Y",$bd);
}