Clean a CSV file

See what is wrong with the file first, then pick the fixes. Nothing changes until you tick a box, and you can check every change before you download.

Processed locally in your browser. File contents are not uploaded. No account needed.

Prefer a full-screen workspace? Open Rote Workspace — the same tools in one place.

Open a CSV file or an Excel workbook to clean

Drag a file here, or choose one: CSV, TSV or TXT up to 50.0 MB, Excel .xlsx up to 10.0 MB. Processed locally in your browser. File contents are not uploaded.

How it works

1. Open the file

Drop a CSV on the page or choose it. The separator (comma, semicolon, tab or pipe) and the text encoding are detected for you, and you can change the separator if the guess is wrong.

2. Read what was found

Empty rows and columns, cells with spaces at either end, blank or repeated headers, rows that repeat exactly, blank cells, values spelled with different capitalisation, and dates like 03/04/2024 that read two ways. Finding a problem does not change anything.

3. Choose fixes, check, download

Tick only the fixes you want. The preview shows changed cells highlighted and, in the Before view, the rows that would be removed. Untick a fix to undo it — the original file is kept untouched until you download.

What it never does

  • Remove a row just because some cells are blank.
  • Turn text into numbers — 00501 keeps its zeros.
  • Reformat dates, or guess which way round an ambiguous date is.

Limits

CSV files up to 50 MB; Excel workbooks (.xlsx) up to 10 MB, one sheet at a time — formulas are not recalculated (the values Excel saved are used) and older .xls files are not supported. The download is a UTF-8 CSV with the same separator as your file (a comma for a workbook); tick “Excel-friendly” if Excel shows accented letters wrongly.

Privacy

Your file is processed locally in your browser, in a background worker on this page. Its contents are not uploaded. The site counts page views and a few anonymous usage events with Umami; they never include file names or contents.

Other free tools

Doing the same clean-up every week? Rote Assistant, the desktop app (coming soon), saves the steps as a job and runs them on next week's file — and tells you when the columns change. Get Rote Assistant.