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What This Remove Duplicates Tool Offers
Remove duplicate rows from CSV. Dedupe by entire row or by a single column; when by column, choose from a dropdown that shows header names. Optionally use case-sensitive comparison for the column. See a summary (e.g. 100 rows to 85 unique, 15 removed) and a preview table (first 25 rows), then download or copy. All processing is client-side—no upload to any server.
- Dedupe by full row or by column: By full row: two rows are duplicates only if every cell matches. By column: choose the column from a dropdown (with header names when available); duplicates are based on that column only.
- Case-sensitive option: When dedupe by column is on, you can enable Case-sensitive so that A and a are treated as different values. By default comparison is case-insensitive.
- Summary: After deduplication you see total rows before, unique rows after, and how many duplicates were removed (e.g. 100 rows to 85 unique, 15 duplicates removed).
- Preview table: First 25 rows are shown in a table with a sticky header; the full CSV is in a textarea below.
- First occurrence kept: For each duplicate set, the first row encountered is kept; later duplicates are removed.
- First row as header: When present, the first row is preserved as header and only data rows are deduplicated.
- Auto or custom delimiter: Choose Auto to detect the delimiter or pick comma, semicolon, tab, or pipe.
- Encoding for file upload: Select UTF-8, Windows-1252, or ISO-8859-1 when uploading a file.
- Client-side and private: Processing happens in your browser; nothing is sent to a server.
Why Remove Duplicates?
Removing duplicates cleans data for analysis, imports, and reporting, and reduces file size when the same rows appear multiple times. Dedupe by column when only one field (e.g. ID or email) should be unique; use case-sensitive when that field distinguishes case.
Powered by browser APIs and client-side processing.
Options at a Glance
- By full row: Two rows are duplicates only if every cell matches.
- By column: Choose the column (dropdown shows header names). Rows with the same value in that column are duplicates; first occurrence kept.
- Case-sensitive: When by column, enable to treat A and a as different (e.g. for IDs).
Frequently Asked Questions
What does dedupe by column mean?
When enabled, only the selected column is used to detect duplicates. Rows with the same value in that column are considered duplicates; the first occurrence is kept. The column dropdown shows header names when your CSV has a header row.
What is case-sensitive for column dedupe?
When dedupe by column is enabled, case-sensitive determines whether A and a are the same. By default (case-insensitive), they are treated as duplicates. Enable case-sensitive to keep both.
What delimiters are supported?
You can use Auto to detect from the first line, or choose comma, semicolon, tab, or pipe.
Is my data secure?
Yes. Deduplication runs entirely in your browser. Your data never leaves your device.