Clean a messy CSV or Excel file online

Keep leading zeros and long IDs intact

A CSV account code such as 00123 must not become 123. A long identifier must not be rounded, and 01/02/2026 must not be guessed as a date in a different locale. We read CSV values as text and keep these strings unchanged while cleaning eligible clutter elsewhere.

For example: a Name cell containing ' Alice ' can become 'Alice', while an ID cell containing '00123', an amount written '1.00' and a blank optional field keep their values. CSV downloads preserve the detected separator and line-ending format.

Excel can still convert values when you open a CSV directly. To inspect identifiers safely, use Excel Data > From Text/CSV and set identifier columns to Text. CSV has no cell-type metadata; no CSV cleaner can control a later application's import settings.

What this cleaner actually does

There is no general “make my data tidy” button. The tool looks for four safe structural problems and, if you later download a cleaned file, applies only those:

It also reports missing cells and formulas. Missing cells are not filled. Formulas turn automatic cleaning off.

• Duplicate rows (exact whole-row copies after trimming eligible ordinary-text edges)
• Completely empty rows
• Completely empty columns
• Leading and trailing whitespace on ordinary words, excluding protected values

The three steps

Upload a .csv or .xlsx file, up to 10 MB. Analysis is free. We analyse the first worksheet and check workbook safety. Additional sheets and complex workbook features disable automatic cleaning.

Review the result. Safe fixes are listed separately from issues we will not touch. Your original file on your computer is still the original.

If you want the cleaned spreadsheet, pay once to download it. If you do not, stop after the analysis. There is no account and no subscription.

What “messy” does not include

We will not split names, standardise dates, guess missing postcodes, or rewrite formulas as values. The file is uploaded for analysis, stored temporarily, and deleted within 24 hours. It is not made public.

If another tool promises a fully automatic cleanup with no review, read the list of changes carefully. A repeated row may still have meaning. Confirm unwanted copies and review the proposed changes before paying.

CSV and Excel

CSV is still the common export from CRMs, banks, and admin tools. Excel (.xlsx) is the common working file. Both are accepted. Older .xls files and Google Sheets links are not. Macros are not executed.

Start with analysis even if you think the file is already clean. If nothing safe is found, you will see that — and you will not be asked to download a cleaned copy.