Tool category
Spreadsheet Utilities
Small browser-local spreadsheet utilities for column letters, date serials, and CSV headers.
Utility preview
These examples show the deterministic local outputs before you open a utility.
Column number 27
AA Column letter AA
27 Excel serial 46023
2026-01-01 CSV header cleanup
Customer Name,Invoice # -> customer_name,invoice Excel Column Letter Converter
Convert Excel or Google Sheets column numbers to letters and column letters back to numbers locally in your browser.
UtilityLocal
Excel Date Serial Converter
Convert ISO dates to Excel serial numbers and Excel serial numbers back to dates with local browser logic.
UtilityLocal
CSV Column Cleaner
Clean CSV header names into simple lowercase spreadsheet-friendly column names locally in the browser.
UtilityLocal