Data Cleaning Tool
Clean CSV data: trim and normalise spaces, remove empty rows, change case, and reformat dates and numbers with explicit input conventions. See before/after and flagged values.
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About the Data Cleaning Tool
Data Cleaning Tool applies common clean-up steps to selected CSV columns: trimming, collapsing repeated spaces, removing fully empty rows, changing case, and reformatting dates and numbers.
Ambiguous dates such as 03/04/2026 are only converted using the day/month order you choose, and numbers use the decimal and thousands separators you specify. Values that cannot be converted safely are flagged and left unchanged, and identifiers with leading zeros or more than 15 digits are protected unless you explicitly allow it. A before/after preview shows every changed cell.
How to use
- Upload or paste CSV data.
- Choose the columns and the text clean-up steps.
- Optionally choose date and number columns with their input and output formats.
- Review the order of operations, counts, flagged values and before/after preview.
- Download the cleaned CSV, or reset to the imported data.
Key features
- Trim, whitespace normalisation and empty-row removal.
- UPPER, lower, Title and Sentence case.
- Date reformatting with explicit day/month/year order.
- Number reformatting with explicit separators and decimals.
- Flagged values left unchanged; leading-zero and long IDs protected.
- Changed-cell and removed-row counts, before/after preview, reset.
Best practices
- Apply case changes only to name-like columns.
- Check flagged values — they usually need a manual fix.
- Keep ID columns out of number formatting.
Benefits
- Consistent data for imports and reports.
- Transparent: every change is visible.
- Private: runs in your browser.
Frequently asked questions
In what order are operations applied?
Empty rows are removed first, then for each selected column: trim, normalise whitespace, change case, format dates, format numbers. The order is shown in the tool.
How are ambiguous dates handled?
You choose the input order (day-month-year, month-day-year or year-month-day). Values that do not form a valid date in that order are flagged and not changed.
Will my IDs lose leading zeros?
No. Values with leading zeros or more than 15 digits are skipped by number formatting and flagged, unless you explicitly allow converting them.
Is my data uploaded?
No. Files and pasted data are processed only in your browser. Nothing is uploaded or stored, and the tool keeps working offline once the page has loaded.