What is CSV deduplication?
CSV deduplication removes records that match according to selected comparison rules. An exact row match checks every field. Key-based deduplication checks selected fields, such as email addresses, customer IDs, product codes, or URLs, even when other fields differ.
Remove duplicates by email or ID
Select a key column when a record should be unique according to one field. For example, comparing by email can identify repeated contact records. Comparing by product SKU can identify repeated product codes. Review whether keeping the first or last record is appropriate before exporting.
CSV formatting and privacy
The parser supports quoted fields, embedded commas, escaped quotation marks, and line breaks within quoted cells. The output is regenerated as delimited text and therefore may use different quoting or line endings than the original file. All parsing and deduplication happen locally in your browser; data is not uploaded to this website.
Frequently asked questions
Can I remove duplicates using only one column?
Yes. Analyze your data, choose selected-column matching, and select the column that defines a duplicate, such as email or customer ID.
What happens if duplicate rows have different values in other columns?
In selected-column mode, the chosen keep-first or keep-last rule decides which full record remains. The tool does not combine values from matching records.
Does the tool upload my CSV?
No. Your file is read and processed locally in the browser.
Will the output preserve the exact original formatting?
No. It preserves cell values unless trimming or spreadsheet formula protection is enabled, but regenerated CSV may use different quoting and line endings.
What is spreadsheet formula protection?
Some spreadsheet applications interpret cell values beginning with formula characters as executable formulas. The optional protection prefixes such values with an apostrophe; that changes the exported value, so enable it only when appropriate for your workflow.