Round to nearest defined cents

money_round.inc.php

/*
 * Rounds to the nearest 5 cents
 * Modified from @dancameron's version
 * For $mode values see http://php.net/manual/en/function.round.php
 * 
 * @param float $amount
 * @param int $mode (default = PHP_ROUND_HALF_UP)
 * @return float
 */
function round_money($amount = 0.0, $mode = PHP_ROUND_HALF_UP) {

    // check if $mode is valid
    if (!in_array($mode, [PHP_ROUND_HALF_UP, PHP_ROUND_HALF_DOWN, PHP_ROUND_HALF_EVEN, PHP_ROUND_HALF_ODD]) {
        $mode = PHP_ROUND_HALF_UP;
    }
    
    $whole = $amount * 100;
    $rounded_whole = round(($whole * 2) / 10, $mode) * $cents;
    $rounded = $rounded_whole / 100;
    
    return $rounded;
}