Runs in your browser · nothing is uploaded
CSV Cleaner & Deduplicator
Remove duplicate and empty rows from a CSV by the columns you choose, see exactly what was removed and why, and download a clean file — without your data leaving the browser.
How duplicates are found
- The file is parsed as CSV — quoted commas and line breaks stay inside their cell.
- If you chose trimming, spaces are trimmed first, so “ Ana ” and “Ana” match.
- Each row's key is the values in your chosen columns (or the whole row).
- The first — or last — row with each key is kept; the others are listed as removed with the line they duplicate.
Example
Matching on email with “Ignore case”, the rows 00124,BEN@example.com and 00124,ben@example.com are duplicates. Keep first keeps the upper-case one exactly as written; keep last keeps the second. The ID 00124 is never turned into 124.
Frequently asked questions
How do I remove duplicates from a CSV?+
Paste the CSV or open the file, tick the columns that identify a duplicate — an email or customer ID, say — or leave them all unticked to compare whole rows. Choose whether to keep the first or last copy, then download the cleaned file. Removed rows can be downloaded separately with the reason for each.
Will it change my numbers, dates or IDs?+
No. Every value is treated as text, so 00123 stays 00123, long numbers aren't rounded and dates aren't reformatted. Only the options you choose — trimming spaces, removing empty rows and duplicates — change anything.
Does it handle commas and line breaks inside quotes?+
Yes. It uses a full CSV parser, so a quoted field like "Smith, John" or a note spanning two lines stays one cell. If a quote is never closed you'll see a warning.
Can it ignore upper and lower case?+
Yes — choose “Ignore case” and ANA@EXAMPLE.COM matches ana@example.com. The row you keep is written exactly as it was.
Which delimiters work?+
Comma, semicolon, tab and pipe. The delimiter is detected from the first lines, and you can override it. You can also choose the delimiter for the download.
Is my file uploaded?+
No. The CSV is read and cleaned in your browser; nothing is sent anywhere or stored.