remove duplicates csv
Remove Duplicates — just pick a file and you're done.
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xlsx, csv files · up to 10MB · first sheet only
Your file never leaves your browser — nothing is uploaded anywhere.
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What to do next
Combines multiple Excel/CSV files into one sheet or one workbook.
Deletes rows that are empty or contain only whitespace.
Cleans up leading/trailing spaces, repeated spaces, and line breaks in one pass.
How to use Remove Duplicates
- 1Choose the Excel (XLSX) or CSV file you want to de-duplicate, or drop it into the upload area.
- 2Confirm whether the first row is a header, then decide whether to compare all columns or only specific ones.
- 3Click Remove duplicates, check the cleaned-up rows in the preview, then download the result.
When to use this
- Handy when a mailing list or form responses have the same email or phone number entered more than once.
- Useful after combining spreadsheets from different systems or teammates, to clear out rows that got duplicated along the way.
- Good for order or product lists where a repeated ID number should only be counted once.
Frequently asked questions
Which row gets kept when several rows are duplicates?
You choose with the ‘Which duplicate row to keep’ option. ‘The first matching row’ keeps the earliest row from the top and removes the ones after it; ‘The last matching row’ does the opposite and keeps only the last one. ‘None’ removes every row that has 2 or more matches, leaving only rows with no duplicate. Either way, the order and formatting of the rows you keep stay exactly as they were.
If I only compare certain columns, what happens to the rest of the data?
Only the columns you select are checked for a match — the full row, including every other column, is kept exactly as-is in the file that gets saved.
Does my file really never get sent to a server?
Correct — LocalSheet does all its processing inside your own web browser. Your file data never travels over the network to anywhere. It even works with your internet connection turned off.
Is there a limit on file size or number of files?
For browser performance and stability, we support files totaling up to 10MB. Merging files supports up to 20 files at once.
Is there a fee, or do I need to log in?
No. Every LocalSheet tool is completely free, with no account and no login required.