ChemDataDoctor
Check and clean CAS numbers in Excel or CSV files
About ChemDataDoctor
ChemDataDoctor is a browser tool for people who work with chemical lists in spreadsheets. Users open an Excel or CSV file, or paste cells from a spreadsheet, and the tool checks CAS Registry Number format and check digits, tidies spacing, normalizes dashes and flags duplicate entries.
The tool is aimed at lab staff, chemical compliance teams and researchers who need a cleaner copy of their data without risking their original file. It shows which values pass, which need review and which look like dates that Excel converted by mistake. Original values stay alongside the cleaned results in the downloaded copy.
Files are processed on the user's device, and the tool is free with no account needed. It also includes guides on keeping CAS numbers intact in Excel and cleaning identifier lists. A passing check digit does not confirm that a substance is registered or correct, and the site is clear that results still need manual verification.
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