Preview duplicate rows
Paste a table, choose which columns identify a match, and see exactly which rows would be kept. Download a new CSV when the result looks right.
Start with your table
Limit: 500 data rows, 30 columns, 100,000 UTF-8 bytes. Values are read as text. Your pasted table stays in this page until you clear it or reload.
Choose what makes a duplicate
Defaults: all columns selected, case-sensitive, whitespace significant, keep first. All selected values must match. Other columns are kept in the output.
Matching options
Blank cells are compared as values. Fully blank rows with the expected column count remain in the table.
Matching uses JavaScript lowercase and trim when selected; it does not normalize Unicode or promise language-specific case rules. Original cell strings remain unchanged.
Review your rows
Row numbers refer to your original input, including the header when selected. Quoted line breaks belong to a single record. Scroll the table sideways to inspect every column.
No duplicates with these rules
All input rows will be kept. You can select fewer key columns to compare a different part of each row.
Download and copy use the same CSV: original cell text, a UTF-8 BOM, comma separators, CRLF records and quoted fields where needed. This does not retain Excel formatting. Excel may interpret IDs and dates when opening CSV; import columns as text when that matters.
The CSV is selected. Use your device’s Copy command, then paste into a text editor or save as a CSV file. It is comma-delimited CSV, not tab-separated Excel cells.
Worked example: match the order, not its amount
Load the small example. With all three columns selected, all five rows are kept because the two A-101 orders have different amounts. Uncheck Amount and preview again: row 4 is a duplicate of row 2, leaving four rows. Change Keep to Last and row 4 is kept instead. The original row order and amounts stay intact.
Use the result in Excel
CSV stores text and cannot preserve formulas, formatting or multiple sheets. To protect leading-zero identifiers, use an import workflow that assigns those columns a Text type. Review our CSV import guide before opening the file. Export here is blocked for cells starting with control characters or formula-like prefixes, including negative numbers; this is a conservative check, not a guarantee about every spreadsheet client.
Microsoft’s Find and remove duplicates explains Excel’s destructive removal command. Our preview compares pasted text with the policy shown above, so Excel’s type and formatting rules may produce different matches. The browser tool works independently of your Excel version. For Excel’s own command, use Microsoft’s instructions for your platform; ribbon locations can differ on Windows, Mac and the web.
For non-destructive review, highlight repeated rows. For two independent sources, compare two lists. Browse tutorials or Excel tips.