How duplicate-row removal works
Load a CSV, TSV, JSON array, Excel spreadsheet, or pasted table. The tool groups records that match exactly, either across all columns or across the key columns you select. Choose automatic retention or review each group, then preview the counts before exporting retained rows, removed rows, or a JSON report. Processing happens in your browser.
Choose matching and retention options
In Match by, choose Full record (all columns) when every column must match. Choose Selected key columns when only selected fields, such as an ID or email, define a duplicate. Select at least one key column; otherwise the tool shows an alert.
In When duplicates are found, choose Keep first occurrence, Keep last occurrence, or Manual review per group. The available comparison controls are Ignore letter case when matching, Normalize whitespace (trim & collapse spaces), and Treat blank/empty/null values as equal.
Remove duplicate rows
- Drop a file into the upload area or click browse files. You can also paste a CSV, TSV, or JSON array; the table loads automatically.
- Choose the matching, retention, and comparison settings; the duplicate groups update automatically.
- If you chose Manual review per group, select the record to keep in each group.
- Review the groups before exporting. If any groups remain unresolved, the export asks you to confirm and uses the current default keep selection for those groups.
Review and export the results
Use Export retained (CSV) for the rows kept by the current settings, Export removed (CSV) for the rows removed, or Export full report (JSON) for group details. The removed CSV and JSON report include original-row references. The retained CSV contains the table columns without those reference fields.
Limits and processing notes
Processing is limited to 50,000 records. The tool warns when a table has more than 5,000 records; split larger files when necessary. For XLSX and XLS files, only the first worksheet is processed.
Delimited input uses the first row as headers. For pasted CSV or TSV, the tool chooses the delimiter by comparing comma and tab counts on the first line. This tool performs exact matching only; it does not find fuzzy near-duplicates, deduplicate plain-text lines, or repair malformed delimiters, quoting, or encoding.
Privacy & Security
Your file or pasted data is processed in your browser. Nothing is uploaded to a server, and no account is needed. The browser-processing limit is 50,000 records.
Frequently Asked Questions
How is this different from the CSV Cleaner?
CSV Cleaner repairs delimited-file structure - delimiters, quoting, ragged rows, encoding. This tool assumes your table already parses correctly and focuses only on finding and removing duplicate records.
How is this different from Fuzzy Duplicate Finder?
Fuzzy Duplicate Finder scores text similarity to catch near-duplicates. This tool only matches records that are exactly equal, after your chosen blank/case/whitespace normalization, on the full row or selected key columns.
Does this deduplicate plain text lines?
No. This tool works on structured records with columns. For deduplicating plain lines of text, use Text Tools instead.
What does manual review mode do?
Instead of automatically keeping the first or last matching record, manual review shows every duplicate group and lets you pick which record to keep per group before anything is removed.
Does this tool modify or upload my data?
No. Everything runs locally in your browser. You export retained, removed, or report files only when you choose to.