Amount to words (Indian Currency)

amountToWords.php

<?php

function amountToWords($number) {
    $no = floor($number);
    $decimal = round(($number - $no) * 100);

    $words = array(
        0 => '', 1 => 'One', 2 => 'Two', 3 => 'Three',
        4 => 'Four', 5 => 'Five', 6 => 'Six', 7 => 'Seven',
        8 => 'Eight', 9 => 'Nine', 10 => 'Ten', 11 => 'Eleven',
        12 => 'Twelve', 13 => 'Thirteen', 14 => 'Fourteen',
        15 => 'Fifteen', 16 => 'Sixteen', 17 => 'Seventeen',
        18 => 'Eighteen', 19 => 'Nineteen', 20 => 'Twenty',
        30 => 'Thirty', 40 => 'Forty', 50 => 'Fifty',
        60 => 'Sixty', 70 => 'Seventy', 80 => 'Eighty', 90 => 'Ninety'
    );

    $digits = array('', 'Thousand', 'Lakh', 'Crore');
    $str = array();

    // Safely convert any number <= 999 into words
    function convert_hundred($num, $words) {
        $output = '';
        if ($num > 99) {
            $output .= $words[floor($num / 100)] . ' Hundred';
            $num = $num % 100;
            if ($num > 0) $output .= ' and ';
        }
        if ($num > 0) {
            if ($num < 21) {
                $output .= $words[$num];
            } else {
                $output .= $words[floor($num / 10) * 10];
                if ($num % 10 > 0) {
                    $output .= ' ' . $words[$num % 10];
                }
            }
        }
        return $output;
    }

    // Indian grouping: last 3 digits, then 2 by 2
    $levels = array();
    $levels[] = $no % 1000;  // Last 3 digits
    $no = floor($no / 1000);
    while ($no > 0) {
        $levels[] = $no % 100;
        $no = floor($no / 100);
    }

    foreach ($levels as $i => $part) {
        if ($part == 0) continue;
        $label = $digits[$i] ?? '';
        $str[] = convert_hundred($part, $words) . ($label ? ' ' . $label : '');
    }

    $rupees = implode(' ', array_reverse($str));
    $paise = '';

    if ($decimal > 0) {
        $paise = convert_hundred($decimal, $words) . ' Paise';
        $paise = ' and ' . $paise;
    }

    return 'Rupees ' . trim($rupees) . $paise . ' Only';
}