Drop in the messy file. Take out the clean one.

Spaces, mixed date styles, euro signs, shouting names, duplicates, broken emails. It is fixed here, in your browser. The file is never uploaded: this page has nowhere to send it. Switch your Wi-Fi off and it still works.

The sample is made up (a fictional bakery). Your own file stays on your device.

Drop a CSV or Excel file here

Or choose one, paste a table straight from Excel (Ctrl+V), or try the sample. I read .csv, .tsv, .txt and .xlsx. Anything I am not sure about stays red and waits for you.

What it does, and what it never does

Does

  • Trims extra spaces and line breaks.
  • Dates in any common style become YYYY-MM-DD (also "5 Nov 2026", English, Italian and Russian month names).
  • Money and numbers lose the euro sign, the decimal comma and the thousands separators, and become real numbers.
  • Names in ALL CAPS or all lower case get proper capitals. Mixed-case names are left alone.
  • Emails are lower-cased and checked.
  • Duplicate rows are removed once, and listed so you can see which.
  • Repeated words (paid, Paid, PAID) get one spelling, the most common one.

Never

  • Guesses. A cell I cannot be sure about stays as it was, turns red and waits for your decision. Click it to type the answer.
  • Uploads. There is no server behind this page. The file is read in your browser's memory and gone when you close the tab.
  • Deletes quietly. Every changed cell and every removed row is in the report and in the "What changed" sheet.
  • Invents. An empty cell stays empty. No made-up emails, no averages.

Limits, said straight: one sheet at a time (pick it above), formulas become their values, merged cells are not kept, old .xls files need saving as .xlsx first, and files over about 40 MB are refused. The Excel file I write was opened in LibreOffice, not in Microsoft Excel itself. If your file does something odd, send it to me and I fix the rule.

Your files are weirder than this?

I can build a cleaner shaped to your exact file and your rules. Same idea: runs on your device, you get the source.

Ask for yours See the shelf

Or read the case behind it: the Excel cleanup and dashboard.