Excel Column Letter to Number Converter: A to 1, AA to 27

Convert Excel column letters to numbers online

Paste a column label such as A, Z, AA or XFD into the converter. The tool converts letters to the 1-based column index used by Excel. For example, AA is column 27, not column 26: the first 26 columns run from A through Z.

A → 1
Z → 26
AA → 27
AZ → 52
BA → 53
ZZ → 702
AAA → 703
XFD → 16384

Column names are case-insensitive: aa and AA both return 27. The converter accepts column labels rather than complete cell addresses, so enter AA, not AA15.

Convert Excel column numbers to letters

Type a positive whole number to get its Excel column label. For example, 1 becomes A, 27 becomes AA and 16384 becomes XFD. Both directions use Excel's current worksheet limit of 16,384 columns.

1 → A
26 → Z
27 → AA
52 → AZ
703 → AAA
16384 → XFD

Values such as 0, 16385, negative numbers, decimal numbers and non-letter column names are invalid. The tool reports an error instead of inventing a column outside Excel's range.

Convert a list of Excel columns in one step

Paste multiple labels or numbers, one per line. You can also separate entries with commas, semicolons or tabs. Each item is converted independently, so you can mix letter labels and numeric indexes in the same input.

A
AA
XFD
1
27

Expected results are A → 1, AA → 27, XFD → 16384, 1 → A and 27 → AA. This is a text converter: it does not open, modify or upload an .xlsx workbook.

Excel formulas for column letters and numbers

If you prefer to do the conversion inside a spreadsheet, the Excel formula =COLUMN(AA1) returns 27. To convert a column index in cell A1 to a column label, use =SUBSTITUTE(ADDRESS(1,A1,4),"1","") in Excel versions that use commas between function arguments. When your Excel locale requires semicolons, change the argument separators accordingly.

For instance, if cell A1 contains 27, the formula returns AA. If your Excel formulas have comma/semicolon compatibility problems, try the Excel formula separator converter and check the resulting formula in your workbook.

Common questions about Excel column indexes

What number is column XFD?

XFD is column 16,384, the final column in modern Excel worksheets. The tool intentionally rejects larger indexes.

Is Excel column numbering zero-based?

No. Excel worksheet columns start at 1 for A. Some programming APIs use zero-based indexes, so check the convention before passing these values into VBA or another language.

Can I convert many Excel columns without uploading a file?

Yes. Copy the column labels or indexes as text, paste them into the tool and copy the converted result. Conversion runs locally in your browser tab; keep a backup of your workbook before applying results.

See more Excel and VBA guides, browse all free tools, or request custom Excel/VBA help if you need a spreadsheet automation built for your workflow.