Excel Column Letter Converter

How to use

1. 1Type a column letter (A, AB, XFD) or a column number (1, 28, 16384) into the input. The tool detects which way to convert.
2. 2Read the column letters, the one-based column number, and the zero-based index side by side, each with its own Copy button.
3. 3Use the quick buttons to jump to common values like A, Z, AA, ZZ, AAA, or the Excel maximum XFD.
4. 4Switch on Allow beyond Excel max if you are working with Google Sheets or another tool that allows more than 16,384 columns.
5. 5Switch to Batch mode and paste a column of values from a spreadsheet to convert many lines at once. Mixed letters and numbers are supported.
6. 6Browse the reference chart for A to Z, the rollover into double letters, and the milestones near the Excel ceiling.

About this tool

Excel Column Letter Converter translates between spreadsheet column letters (A, B, AA, AB, XFD) and column numbers (1, 2, 27, 28, 16,384) in your browser, in either direction. The direction is detected automatically, so you can type AB to get 28, or type 28 to get AB, without choosing a mode. The conversion uses Excel's bijective base-26 system, the same lettering scheme Google Sheets, Apple Numbers, OpenDocument spreadsheets, openpyxl, ExcelJS, Google Apps Script, and VBA all share. Unlike a straight base-26 encoding, bijective base-26 has no zero digit, so the single-letter range A..Z covers 1..26, then AA..ZZ covers 27..702, then AAA..ZZZ covers 703..18,278, and so on. The tool reaches the standard Excel and .xlsx maximum of XFD (16,384) by default, and an Allow beyond Excel max switch unlocks larger values for Google Sheets and other tools that allow more columns. Letter input is trimmed, upper-cased, and validated; non-letter characters produce a specific error so paste mistakes are easy to spot. Number input accepts commas, underscores, and spaces as digit separators, and rejects zero and negatives because column 0 does not exist. A zero-based index is shown alongside the one-based column number, which is what openpyxl's column_index_from_string, pandas DataFrame.iloc, ExcelJS, and other libraries actually need. A batch mode accepts a column of mixed letters and numbers pasted from a spreadsheet, converting each line independently and returning a parallel column ready to paste back. A reference chart covers the full A..Z range, the rollover into double letters where most confusion happens, and the milestones near the Excel XFD ceiling, plus a short explainer of why this is not the same as regular base-26. Useful for figuring out which column letter a numeric index points to, looking up the index for a column letter in openpyxl, pandas, or ExcelJS, double-checking VBA Range references, decoding column letters in SQL queries that join spreadsheet exports, and any moment you would otherwise reach for a calculator and a piece of scratch paper. Conversion runs entirely in your browser; the values you type or paste are never uploaded.

Free to use. Works in your browser. No signup, no login.