Find the column number of any Excel column letter, such as AB = 28
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.Code that reads a spreadsheet usually wants a column number, while the sheet itself shows letters. Type the letters and read the number: AB is 28, ZZ is 702, and XFD, the last column Excel has, is 16,384. A full cell reference such as $AB$12 or Sheet1!C3 works too, and the row is shown separately.
Open the page with AB already converted to 28.
Type your column letters, or a full reference such as Sheet1!C3.
Read the Number; the row from a cell reference is shown separately.
Press Copy number to take it.
Paste a list for a whole mapping at once.
This converter turns Excel column letters into column numbers and numbers back into letters. Type AB and it shows 28; type 28 and it shows AB. It works out which direction you mean from what you type, so there is no mode to switch. Cell references are understood as well: $AB$12, ab12 and Sheet1!C3 all give the column, with the row shown on its own.
Excel has 16,384 columns and 1,048,576 rows per worksheet, according to Microsoft's published specifications, so the last column is XFD. Larger numbers still convert, with a warning, because other spreadsheet programs and libraries have their own limits.
What it does not do: convert R1C1 references, rename columns in a file, or read a workbook. For Excel date serial numbers such as 45292, use the Excel Date Serial Converter. Everything runs in your browser and nothing is sent anywhere.
The rest of the article, and all 6 questions about Excel Column Letter Converter, are on the Excel Column Letter Converter page.
XFD is column 16,384, the last column in an Excel worksheet since Excel 2007. The sum is X (24) times 676, plus F (6) times 26, plus D (4), which gives 16,224 + 156 + 4. Earlier versions of Excel stopped at column IV, number 256.
Column letters have no zero digit. In ordinary base 26, the number after Z would be written A0; in a spreadsheet it is AA. So each step subtracts one before dividing by 26. Code that skips that step fails on Z, AZ, ZZ and every other column ending in Z.
Yes. Dollar signs, lower case and a sheet name before an exclamation mark are all accepted, so $B$7, b7 and 'My Sheet'!B7 all give column B, number 2, with row 7 shown separately. R1C1 references are not supported.
Yes. Google Sheets, LibreOffice Calc and Numbers use the same lettering, so A is 1, Z is 26 and AA is 27 everywhere. Only the maximum number of columns differs between programs, which is why the Excel limit is shown as a warning, not an error.
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