estimation of motor vehicle importation costs (including, importation duty payable) in Kenya.

duty_payable.php

<?php

/**
 * A simple PHP function that calculates an estimation cost for car importation into kenya.
 * 
 * @param int $cif This is the customs value of the vehicle i.e. the Cost, Insurance & Freight paid for the vehicle.
 * @param int $clearance This is the clearing Agent's sum fee together with some other port handling charges.
 * @param int $import_duty This is 25% of the CIF value of the vehicle.
 * @param int $excise_duty This is 20% of the (CIF value + Import Duty).
 * @param int $vat This is 16% of the (CIF value + Import Duty + Excise Duty).
 * @param int $idf This is 2.25% of the CIF value or Ksh. 5,000, whichever is higher, is payable.
 * @return string This is the final result.
 */
public function duty_payable($cif = 440000, $clearance = 50000) : String
{
    $payable              = new stdClass;
    $payable->import_duty = getPercentOfNumber(25, $cif);
    $payable->excise_duty = $cif + $payable->import_duty;
    $payable->vat         = getPercentOfNumber(16, ($cif + $payable->import_duty + $payable->excise_duty));
    $payable->idf         = getPercentOfNumber(2.25, $cif) >= 5000 ? getPercentOfNumber(2.25, $cif) : 5000;

    return number_format($payable->import_duty + $payable->excise_duty + $payable->vat + $payable->idf + $clearance, 2);
}

// load into script as a helper method.
if (! function_exists('getPercentOfNumber')) {
    /**
     * A simple PHP function that calculates the percentage of a given number.
     * 
     * @param int $percent The percentage that you want to calculate.
     * @param int $number The number you want a percentage of.
     * @return int The final result.
     */
    function getPercentOfNumber($percent, $number) : int
    {
        return ($percent / 100) * $number;
    }
}