pmt.php

<?php

function pmt($interest, $payments, $pv, $fc = 0.00, $type = 0)
{
    $xp = pow((1 + $interest), $payments);
    return
        ($pv * $interest * $xp / ($xp - 1) + $interest / ($xp - 1) * $fc) *
        ($type == 0 ? 1 : 1 / ($interest + 1));
}