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Remove duplicate rows from CSV or Excel

Drop a CSV or Excel file, choose whether a "duplicate" means an identical row across every column or a repeated value in one key column — an email address, a customer ID — and download the cleaned file with an exact count of what was removed. Everything runs in your browser, which matters for a contact list or a spreadsheet full of names.

  • Nothing you type leaves this page
  • Works offline once loaded
  • Free forever, no signup
Drop a .csv, .xlsx or .xls file here, or tap to choose Client lists, contact exports — nothing is uploaded, it stays in this tab

How to use this tool

  1. Drop your CSV or Excel file

    Or load the sample to see the matching options in action.

  2. Choose what counts as a duplicate

    Match on every column, or pick a single key column such as email or invoice number.

  3. Remove duplicates and download

    The result downloads in the same format the file came in, with a count of exactly how many rows were removed.

Questions people ask

How do I remove duplicate rows from a big CSV or Excel file?

Drop the file, pick which column (or all columns) must match for two rows to count as duplicates, and click Remove duplicates — the cleaned file downloads with the exact count of what was removed.

What is the difference between matching on "all columns" versus one key column?

"All columns" only removes rows that are identical across every field — a true exact duplicate. Matching on one key column (like Email) removes any row that repeats that value, even if the other columns differ — useful when the same person appears twice with slightly different spellings elsewhere in the row.

Does it matter if two entries differ only in case, like [email protected] vs [email protected]?

By default the comparison is case-insensitive and trims stray whitespace, so those two would be treated as the same value — turn "case-sensitive" on if you need an exact character-for-character match instead.

What file do I get back — CSV or Excel?

Whichever format you uploaded. Drop a CSV and you get a cleaned CSV back; drop an Excel file and you get a cleaned .xlsx, so nothing about the format changes except the duplicate rows being gone.

Is my file uploaded anywhere?

No. Reading the file, comparing rows and writing the cleaned file all happen in your browser — this is exactly the kind of tool where a client list or salary sheet should never leave your device, and here it never does.

Related tools

Bookmark this page — the tool keeps working offline, and your settings stay in this browser. Built by Dynamb Technologies, who make software for a living.