Snippet on how to get WTAX in the Philippines.

PayrollHelpers.php

<?php

public function getWitholdingTax()
    {
        // Check if within minimum wage salary, then 0 tax
        // Check from general settings
        $general_settings = Settings::first();
        if ($this->getBasicPay() <= $general_settings->minimum_pay)
            return 0;

        $min = array(
            array(
                //15 Days and Below
                array(2083, 2500, 3333, 5000, 7917, 12500, 22917),   //0 Dependents
                array(3125, 3542, 4375, 6042, 8958, 13542, 23958),   //1 Dependent
                array(4167, 4583, 5417, 7083, 10000, 14583, 25000),  //2 Dependents
                array(5208, 5625, 6458, 8125, 11042, 15625, 26042),  //3 Dependents
                array(6250, 6667, 7500, 9167, 12083, 16667, 27083),  //4 Dependents
            ),
            array(
                //More than 15 Days
                array(4167, 5000, 6667, 10000, 15833, 25000, 45833),     //0 Dependents
                array(6250, 7083, 8750, 12083, 17917, 27083, 47917),     //1 Dependent
                array(8333, 9167, 10833, 14167, 20000, 29167, 50000),    //2 Dependents
                array(10417, 11250, 12917, 16250, 22083, 31250, 52083),  //3 Dependents
                array(12500, 13333, 15000, 18333, 24167, 33333, 54167),  //4 Dependents
            )
        );

        $percentage = array(0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.32);   //Salary Excess

        //Additional deduction for tax
        $add = array(
            array(0, 20.83, 104.17, 354.17, 937.50, 2083.33, 5208.33),   //15 Days and Below
            array(0, 41.67, 208.33, 708.33, 1875, 4166.67, 10, 416.67),   //More than 15 Days
        );

        $dependents = $this->getTotalDependents();

        if ($this->working_days <= 15) {
            $period = 0;
        } else {
            $period = 1;
        }

        for ($x = count($percentage) - 1; $x >= 0; $x--) {
            // Find basic_pay range
            if ($this->getNetAfterContributions() >= $min[$period][$dependents][$x]) {
                //Compute witholding tax
                $tax = $this->getNetAfterContributions() - $min[$period][$dependents][$x];
                $tax *= $percentage[$x];
                $tax += $add[$period][$x];
                break;
            } else {
                $tax = 0;
            }
        }

        return round($tax, 2);
    }