How to Autofill Letters in Excel: A to Z and Beyond

Excel can fill numbers, dates, and familiar built-in series, but a single typed letter is usually copied rather than continued as A, B, C. To autofill letters in Excel, enter a formula that converts a number into a letter, then use the fill handle. For a one-time alphabet column, this works in older desktop versions too. If you need labels after Z or want to reuse the sequence, use one of the options below.

Autofill A to Z with the fill handle

Start in cell A1 so the row reference in the formula matches the first position in the sequence. Keep the cells below it empty if you want the letters to fill into a clear column.

1. Select A1, type =CHAR(ROW(A1)+64), and press Enter. ROW(A1) returns 1; adding 64 gives the character code 65, which CHAR returns as A.
2. Select A1 again. Point to the small square at the lower-right corner of the green cell outline, called the fill handle. Drag it down through A26 and release. The row reference adjusts as the formula is filled, so the results continue B, C, and so on through Z.

For lowercase letters, use =CHAR(ROW(A1)+96) in A1 and fill through row 26. The codes used here cover the standard English alphabet; they do not create accented letters or a custom alphabet.

Generate all 26 letters with SEQUENCE

If your Excel version supports dynamic arrays, enter =CHAR(SEQUENCE(26,,65)) in A1 and press Enter. SEQUENCE returns the numbers 65 through 90, and CHAR converts them to A through Z. Excel places the results in the cells below automatically, so you do not have to drag the fill handle. The lowercase version is =CHAR(SEQUENCE(26,,97)).

Leave the output range below A1 empty before entering the formula. If another value blocks the spill range, Excel shows a #SPILL! error. Microsoft lists SEQUENCE for Microsoft 365, Excel 2021, and Excel 2024; it is not listed for Excel 2019 or Excel 2016. If you have an older version, use the fill-handle formula instead.

Continue past Z with labels such as AA and AB

CHAR follows character codes, so it will not wrap from Z to AA. For an Excel-style column-label sequence, enter this formula in A1:

=SUBSTITUTE(ADDRESS(1,ROW(A1),4),"1","")

Fill the formula down through row 702. ROW(A1) supplies the column number to ADDRESS; the formula returns a reference such as A1 or AA1, and SUBSTITUTE removes the row number. The results run A, B, …, Z, AA, AB, and continue through ZZ. This is useful for labels that should follow the same pattern as Excel column headings. If you need only A to Z, the shorter CHAR formula is easier to maintain.

Save an alphabet as a reusable custom list

If you repeat this task often in Excel for Windows, you can add A through Z as a custom list. First enter the letters in order in a worksheet range and select that range. Open File > Options > Advanced > General > Edit Custom Lists. In the Custom Lists dialog, confirm the selected cell range and choose Import, then click OK to close the dialogs.

After the list is added, type A in a cell and drag its fill handle to continue the alphabet. Custom lists are stored with the Excel installation, so a list added on your computer might not be available for Fill on a colleague’s computer. For a shared workbook, keep a visible A–Z reference range or use a formula so the sequence travels with the file. Microsoft also notes that lists stored in a workbook are not automatically available to the Fill command on another computer.

Fix common autofill problems

• Every cell repeats A: Check that A1 contains the formula, not a manually typed letter, before dragging.
• Symbols appear after Z: The CHAR formula has moved beyond code 90. Stop at row 26 or switch to the ADDRESS formula for labels after Z.
• #SPILL! appears: Clear the cells below the SEQUENCE formula so Excel has room for all 26 results.
• The formula is rejected: Some regional settings use semicolons instead of commas between arguments. Replace the separators if your Excel installation expects them.

Which method should you use?

Microsoft references

• Fill data automatically in worksheet cells
• CHAR function and ROW function
• SEQUENCE function and ADDRESS function
• Create or delete a custom list for sorting and filling data