What is the largest supported column?

Any positive integer is supported, well beyond Excel's own 16,384 column limit.

Is input case-sensitive for letters?

No, lowercase letters are automatically converted to uppercase before calculating.

What happens with invalid letters?

Non A-Z characters trigger a clear validation error.

Is my data uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your input never leaves your device and nothing is logged or stored on our servers.

Does it work offline and on mobile?

Yes. Once the page has loaded it keeps working without a network connection, and the layout is responsive so it stays usable on phones and tablets.

Excel Column Name Converter

Convert between spreadsheet column numbers and letters.

Support

Works Offline

Privacy First

No Login

No API

Number → Column letters

Column number

Column letters → Number

Column letters (e.g. A, Z, AA, XFD)

About the Excel Column Name Converter

Convert a column number to its Excel/Google Sheets letter name (e.g. 28 → AB) or convert column letters back to a number, both updating live as you type.

Popular uses

excel column converter
column number to letter
spreadsheet column converter
a1 notation

Examples

Column 28

Output

AB

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-07 · Runs entirely in your browser