Remove Duplicate Rows from a CSV File
Repeated records can inflate a mailing list, repeat products in an inventory export, or make a report harder to trust. This CSV duplicate remover compares each parsed data row with earlier rows, keeps the first exact match, and removes later copies. Upload a CSV, TSV, or text file, or paste delimited data, then review the result and download a separate CSV.
The tool runs in your browser and does not overwrite the source file. Its matching rule is deliberately exact: every field in a row must have the same value for the row to count as a duplicate.
How This CSV Duplicate Remover Matches Rows
The tool compares complete rows, not selected columns. Values are case-sensitive and space-sensitive, and they are not trimmed or normalized before comparison. The first occurrence stays in its original position; later copies are removed.
| Data row | Result | Reason |
|---|---|---|
A-17,Ada,London | Kept | First occurrence. |
A-17,Ada,London | Removed | Every field matches the earlier row. |
A-17,ada,London | Kept | Ada and ada differ in case. |
A-17,Ada,London | Kept | The final field has a trailing space. |
A-17,Ada | Kept | This row has a different number of fields. |
CSV quotation marks are syntax for grouping field values. A quoted value and an unquoted value can match if they parse to the same text. The header is not compared with data rows; the first row is preserved as the header.
Whole-Row Matching or Key-Column Matching?
Whole-row matching is right when a duplicate means the record repeats across every column. If two rows share an email address but have different names or dates, this tool keeps both because the full rows are not identical.
To deduplicate by email, customer ID, SKU, or a combination of fields, you need a tool that lets you select the columns that define a match. This page has no key-column, case-folding, or whitespace-normalization options. If you only want exact duplicate records, leave the values as they are and run this tool; if you want to normalize spaces first, use the CSV Cleaner and then deduplicate.
How to Remove Duplicate Rows
- Choose Browse CSV File or drop a CSV, TSV, or text file into the upload area. You can also paste delimited data into the text box.
- Check the contents and make sure the first row is the header you want to keep. If the file has no header, its first data row will be treated as the header.
- Select Remove Duplicate Rows. The summary shows data-row and column counts before and after processing.
- Review the preview. Select Download CSV to save the complete result as a new file.
Headers, Row Order, and CSV Structure
The header row is kept as-is and is excluded from duplicate matching. Among the data records, the first copy of each exact row remains, and the order of the kept records follows the input order. The tool does not sort, trim, or change values as part of deduplication.
Rows are compared as parsed fields. A comma inside a quoted cell is part of that cell, not a separator. The tool recognizes common comma, tab, semicolon, and pipe separators, and handles quoted values. If two rows have different field counts, they are different rows even when the visible values look similar.
Preview and Download the Result
The result preview shows the cleaned CSV as text and the summary reports row and column counts before and after. For long results, the preview is shortened at about 7,000 characters. That limit only affects the on-page preview; the downloaded CSV contains all remaining unique rows.
The output is saved as comma-separated CSV, even if the source was TSV or TXT. It is a separate file, so your original remains unchanged. CSV stores text values and does not retain spreadsheet formatting, formulas, or multiple worksheets.
Questions About CSV Duplicate Removal
Can I remove duplicates based on one column?
No. This tool compares the entire row and removes a later row only when every field matches. It cannot match by just an email, ID, SKU, or selected set of columns.
Does it ignore capital letters or extra spaces?
No. Matching is case-sensitive and space-sensitive. Oak and oak are different, as are Oak and Oak . Values are not trimmed before comparison.
Which copy of a duplicate row is kept?
The first occurrence is kept in its original order. Later rows with identical values across all fields are removed.
Is the header row checked for duplicates?
No. The first row is preserved as the header. Duplicate matching applies only to the data rows beneath it.
Can rows with different numbers of fields match?
No. Rows must have the same parsed fields and the same value in every field. A trailing empty field makes the row different from one with no such field.
Can I use TSV or paste text?
Yes. You can open CSV, TSV, or TXT files up to 50 MB, or paste delimited text. The result is downloaded as CSV.
Does the preview show the complete result?
Not always. Long previews are shortened to about 7,000 characters. Download CSV contains the full result.
Are my files uploaded?
No. The file is read and processed in your browser. Its contents are not sent to a server by this tool.
Supported Files and Privacy
The tool accepts CSV, TSV, and plain-text delimited files up to 50 MB. It also accepts pasted data. The parser detects common separators and supports quoted fields. Large files may take longer to read and process, depending on your browser and device. Processing happens locally in the browser.
Related CSV Tools
Use the CSV Cleaner for trimming, blank-row removal, and other cleanup steps, the CSV Validator to check file structure, or browse all CSV tools.