How do I remove duplicates from a CSV file?
Pick the column that identifies a record, usually email, and keep only the first row for each value, ignoring case and extra spaces. Open your file here, choose that column, and download the cleaned CSV.
- Paste the CSV or open the file. The delimiter is detected automatically.
- Choose the column to dedupe on, or Whole row.
- Keep trim, empty row removal and case-insensitive matching on.
- Check the counts and the preview table.
- Download the clean CSV. It opens in Excel with accents intact.
Examples
Duplicate contact with different spacing and case
Input
Email,First Name jane@acme.com,Jane JANE@ACME.COM ,jane
Result
Email,First Name jane@acme.com,Jane
Frequently asked questions
Is there a file size limit?
Only your device's memory. Files with tens of thousands of rows are fine on a normal laptop.
Which duplicate is kept?
The first one in the file. Sort the file first if you want to keep, for example, the most recent record.
Does it change my original file?
No. You get a new download. The original file on your computer is not touched.
Why do accents look wrong when I open the result in Excel?
The download includes a byte order mark so Excel reads it as UTF-8. If you copy and paste instead, use Excel's Data, From Text/CSV import and pick UTF-8.