Free CSV Compare Tool
Compare two CSV files or pasted CSV text and see added, removed, and changed rows. Supports headers, custom delimiters, and key-column matching. Runs locally in your browser.
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How to use
Pick a comparison mode, paste or upload CSV A and CSV B, then run the diff.
- Choose Compare mode: Key column (recommended) or Row index.
- Set Delimiter (comma by default) and whether your CSV has a Header row.
- If using Key column, enter the column name (with headers) or a 1-based column index.
- Click Compare to see the summary and a short list of examples.
FAQ
Is this CSV compare tool really free?
Yes. You can compare CSVs here without paying or signing up.
Does the comparison upload my CSV data?
No. The diff runs in your browser and the tool JavaScript does not send network requests.
What is “Key column” mode?
It matches rows using a unique column (like id) and reports which keys were added, removed, or changed.
What if my CSV uses semicolons or tabs?
Set the Delimiter field to ; for semicolons or paste a tab character for TSV.
How are “changed rows” detected?
A row is “changed” when any cell differs after applying options like Trim cells and Ignore case.
Why am I getting a duplicate key error?
Key mode requires unique keys. If the key column repeats, the tool can’t reliably match rows.
Can I compare CSVs without headers?
Yes. Turn off Header row and use a numeric key column index (1-based), or use Row index mode.
Continue your workflow
Browse related tools by task. Use the improved core tools for a consistent workspace with file import, downloads and clear validation errors.