numberAbbreviation.php

<?php
/**
 * Shorten large numbers into abbreviations (i.e. 15,000 = 15K, 1,500 = 1.5K)
 *
 * @param int    $number  Number to shorten
 * @return String   A number with a symbol
 */ 
function numberAbbreviation($number) {
    $abbrevs = array(12 => "T", 9 => "B", 6 => "M", 3 => "K", 0 => "");

    foreach($abbrevs as $exponent => $abbrev) {
        if($number >= pow(10, $exponent)) {
        	$display_num = $number / pow(10, $exponent);
        	$decimals = ($exponent >= 3 && round($display_num) < 100) ? 1 : 0;
            $display = number_format( $display_num, $decimals );
            if ( $display % 1 === 0 ) {
                $display = number_format( $display, 0 );
            }
            return $display . $abbrev;
        }
    }
}
?>