<?php

    function calculate_easter($year){

        $c = floor($year / 100);
        $n = $year - 19 * floor( $year / 19 );
        $k = floor(( $c - 17 ) / 25);
        $i = $c - floor($c / 4) - floor(( $c - $k ) / 3) + 19 * $n + 15;
        $i = $i - 30 * floor( $i / 30 );
        $i = $i - floor( $i / 28 ) * ( 1 - floor( $i / 28 ) * floor( 29 / ( $i + 1 ) ) * floor( ( 21 - $n ) / 11 ) );
        $j = $year + floor($year / 4) + $i + 2 - $c + floor($c / 4);
        $j = $j - 7 * floor( $j / 7 );
        $l = $i - $j;
        $month = 3 + floor(( $l + 40 ) / 44);
        $day = $l + 28 - 31 * floor( $month / 4 );

        return array($month, $day);
    }


    list($month, $day) = calculate_easter(2005);

    echo "easter sunday in 2005 will be on ".date('jS F', mktime(0,0,0,$month,$day,2005));

?>