# Converting column number Excel column name

Quick little snippet needed while working on a web app that exports to an Excel worksheet. What I needed was a way to convert column numbers to the lettering that Excel uses. So, for example, column 27 would become AA.

Found a bulk of the solution at Stack Overflow. Logic wasn’t exactly what I was after and I needed it in PHP, but that post got me 99% of the way there.

function colByNumber($colNum) {$s = '';
$colNum -= 1; do {$s = chr(ord('A') + ($colNum % 26)) .$s;
$colNum /= 26; } while ((int)$colNum-- > 0);

return \$s;
}


Only note is that I was using one based indexing in my code, but zero based in this function. Easy enough to just subtract 1 from the column number before starting.

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