Simple functions to convert between column number and column names in Excel

excel-column-convert.php

<?php
/**
 * Converts the column number to proper Excel column format
 * 
 * @param $number column number to be converted
 * 
 * @return Returns Excel column name
 */ 
function excelConvertToCell($number)
{
    if ($number <= 26) {
        return chr(ord('A') - 1 + $number);
    } 

    $basic = intval($number / 26);
    $modulus = $number % 26;
    if ($modulus == 0) {
        $basic --;
        $modulus = 26;
    }

    return excelConvertToCell($basic) . excelConvertToCell($modulus);
}

/**
 * Converts Excel column name to column number
 * 
 * @param $number column name to be converted
 * 
 * @return Returns column number
 */ 
function excelConvertToNumber($cell)
{
    $len = strlen($cell);

    if (1 === $len) {
        return ord(strtoupper($cell)) - ord("A") + 1;
    }

    $number = 0;
    for ($i = 0; $i < $len; ++$i) {
        $number += excelConvertToNumber($cell[$i]) * pow(26, $len - $i - 1);
    }

    return $number;
}