How to convert a column number to a letter
✓ Verified in LibreOffice 25.8.7.3 ✓ Verified in Google Sheets (2026-08-30)Turn 28 into "AB" — for building references in formulas, scripts, or documentation.
The formula
| App | Formula | Notes |
|---|---|---|
| Excel (desktop) | =SUBSTITUTE(ADDRESS(1,A2,4),"1","") | ADDRESS builds "AB1" in relative style (4); SUBSTITUTE strips the row. |
| Google Sheets | =SUBSTITUTE(ADDRESS(1,A2,4),"1","") | Identical. |
| LibreOffice Calc | =SUBSTITUTE(ADDRESS(1,A2,4),"1","") | Identical. |
How it works
ADDRESS(1, 28, 4) produces the relative reference "AB1", and stripping the "1" leaves the column letters — safe here because style 4 guarantees the only digit is that row 1. The reverse direction (letter → number) is =COLUMN(INDIRECT(A2&"1")). Mostly useful when generating formulas from data or writing documentation; inside ordinary formulas, INDEX with numeric coordinates avoids needing letters at all.
Verified, not just documented
We ran =SUBSTITUTE(ADDRESS(1,A2,4),"1","") in LibreOffice 25.8.7.3 (headless, with forced recalculation) and it returned AB — exactly the expected result. We then ran the same formulas in Google Sheets, executed 2026-08-30: a formula-only workbook goes into Google Drive, which converts it to a Sheet and recalculates every formula with Google’s own engine, and comes back out as .xlsx carrying the values Google computed. It returned AB for the worked example, the same value LibreOffice produced. Both engines’ numbers on this page are executed results. The Excel formula follows Microsoft’s official documented syntax — we do not run desktop Excel.
Functions used
SUBSTITUTE · ADDRESS — see full Excel, Google Sheets & LibreOffice compatibility for each.
Related recipes
- How to convert currency text like "$1,234.50" to a number
- How to count items in a comma-separated cell
- How to count occurrences of a substring in a cell
- How to count the total words in a range
- How to count the number of words in a cell