CSV Cleaner
Free CSV cleaner. Remove duplicate and empty rows, trim spaces, fix case, find and replace, drop or reorder columns and sort. Private, runs in your browser.
- No upload — 100% private
- Instant, on your device
- Free, no sign-up
- Works offline once loaded
How it works
How to use CSV Cleaner
Drop a CSV file onto the page, or try the messy sample.
Pick the clean-ups you need: trim whitespace, remove empty rows or columns, remove duplicates, change case, or find and replace.
Untick, reorder or sort columns and check the before and after counts in the preview.
Choose the output delimiter, line endings and Excel BOM, then download the cleaned CSV.
Why use it
Why use our CSV Cleaner tool
Remove duplicates
Drop identical rows or rows with the same value in chosen columns (like email), keeping the first or last occurrence, optionally ignoring case.
Whitespace and empty data
Trim leading and trailing spaces, collapse repeated spaces, and remove rows or columns that are completely empty.
Fix broken rows
Rows with too few fields are padded and rows with too many are kept or cut, so every row matches the header.
Find, replace and case
Replace text in one column or all of them (with optional regex), and normalise a column to Title Case, UPPERCASE, lowercase or Sentence case.
Sort, remove and reorder
Sort by any column with numbers sorted as numbers, and remove or reorder columns before you download.
Excel-ready and private
Export with comma, semicolon, tab or pipe, CRLF line endings and a UTF-8 BOM for Excel. Files are processed on your device and never uploaded.
FAQ
Frequently asked questions
How do I remove duplicate rows from a CSV file?
Open the file, set Remove duplicate rows to Identical whole rows — or to Same value in selected columns and tick, for example, Email. Choose whether to keep the first or the last copy, then download the cleaned CSV.
In what order are the clean-ups applied?
Rows are fixed to the right length first, then whitespace is trimmed, find & replace and case changes run, empty rows and columns are removed, duplicates are dropped and finally the rows are sorted. So trimmed values are compared when looking for duplicates.
How does sorting handle numbers?
In Auto mode, a column where every non-empty value is a number (including 1,250.50, $12 or 45%) is sorted numerically, so 9 comes before 10. Other columns are sorted alphabetically with natural number order. Empty cells always go last.
Why does Excel show strange characters in my CSV?
Excel assumes an older encoding unless the file starts with a UTF-8 byte-order mark. Tick Add UTF-8 BOM before downloading and accented letters and symbols display correctly.
How big a CSV can I clean?
Files up to 100 MB can be opened. Cleaning runs in a background worker with a progress bar, and the preview is paginated so even hundreds of thousands of rows stay responsive.
Is my data uploaded?
No. The CSV is cleaned entirely in your browser. Nothing is sent to a server or stored anywhere.
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