ARCHIVED: In Microsoft Excel, why are my columns labeled with numbers instead of letters?

In Microsoft Excel, you can reference specific cells within a worksheet with either Excel's default style or the R1C1 reference style, as long as the formulas in the spreadsheet use the correct style for that sheet. For instance, if you are working in a sheet that uses the R1C1 reference style, typing the formula =SUM(A1:A2) will not work.

In the R1C1 reference style, the first cell in the first row is referred to as R1C1 (Row 1 Column 1), the second cell is referred to as R1C2, and so on.

If you are using the default style, Excel will automatically assign a letter and number combination to each cell. The columns are assigned letters, and the rows are assigned numbers. Thus, the first cell in the first row is referred to as A1, the second cell in the first row is referred to as B1, the first cell in the second row is referred to as A2, and so on.

To change reference styles in a worksheet:

1. In Excel 2010 for Windows, from the File tab, click Options.

   In Excel 2007 for Windows, from the Office Button menu, choose Excel Options.

   In Excel for Mac OS X, from the Excel menu, choose Preferences....

2. In Excel 2010 and 2007 for Windows, click Formulas. In Excel for Mac OS X, click General.
3. Check or uncheck R1C1 Reference Style (Windows) or Use R1C1 reference style (Mac OS X).