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CSV & Excel Cleaner

Clean CSV, TSV, and XLSX data locally with a reviewable change log. Trim text, normalize whitespace and headers, remove duplicates by selected keys, preview rejected rows, undo, and export without uploading the file.

Saved sessions

Drop a CSV, TSV, or XLSX file here

Your source stays in this browser. Legacy .xls files are not supported.

Private spreadsheet cleaning

The source file, preview, operation manifest, and export remain in your browser. BaseToolbox does not receive file contents, headers, cell values, or filenames through analytics.

Current limitations
  • The cleaner supports CSV, TSV, and modern XLSX, but not legacy .xls files or macros.
  • Duplicate removal is exact after the selected text normalization; it does not guess whether similar records are the same person.
  • Formulas are preserved only where the export format and selected operation permit it; desktop Excel recalculation is not performed.
  • Browser storage may be cleared or reclaimed, and private browsing may not retain the source across restarts.

How to clean CSV or Excel data

1

Import and select

Choose a worksheet and select only the cleaning operations you want to apply.

2

Review every change

Compare before and after samples, inspect the operation log, and review any rows marked for removal.

3

Apply and export

Save the operation manifest, keep the source available for undo, and download the cleaned CSV or XLSX.

CSV and Excel cleaner FAQ

Does this tool upload my spreadsheet?
How are duplicate rows detected?
Can I see what changed before exporting?
Can I undo spreadsheet cleaning?

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