Compare CSV Files — Online Diff Tool
Compare two CSV files and highlight differences
Compare two CSV files online and see every difference in seconds. Upload both files and this free CSV diff tool highlights added rows, removed rows, and changed cells with color-coded output — side by side or as a unified diff, like a spreadsheet-aware version of a code diff.
Unlike a plain text diff, rows can be matched by a key column such as an ID, SKU, or email address. That means files that were re-sorted, re-exported, or partially updated still compare correctly — you find the real differences between two CSV files, not noise from row order.
Both files are processed locally in your browser, so nothing is uploaded — safe for comparing customer lists, payroll exports, and other sensitive data. When you are done, export a diff report listing every change for documentation or sign-off.
Original File
Updated File
How to Use
- Upload the two CSV files you want to compare
- Select a key column (like an ID or email) so rows match even if the order changed
- Review the highlighted diff — green for added, red for removed, amber for changed cells
- Filter by change type if you only care about additions, deletions, or edits
- Export the diff report if you need a record of the differences
Features
- Side-by-side comparison with color-coded changes
- Unified diff view for a compact change log
- Match rows by key column (ID, email, SKU) instead of position
- Detects added rows, removed rows, and modified cells
- Filter results by change type to focus on what matters
- Export a diff report of every difference
- Private by design — both files stay in your browser
Use Cases
- Compare two versions of the same export to see what changed between runs
- Verify a data migration by diffing the source and destination extracts
- Check what a colleague edited in a shared spreadsheet before merging
- Audit price lists, inventories, or user lists between two dates
- Confirm a cleanup script changed only the rows it was supposed to
Frequently Asked Questions
How do I compare two CSV files and highlight differences?
Upload both files and the tool highlights every difference automatically: added rows in green, removed rows in red, and changed cells in amber. You can review them side by side or as a unified diff and export the result.
What differences does the tool detect?
It detects rows that exist in one file but not the other (added/removed) and rows that exist in both but have one or more changed cell values — down to the individual cell.
How do I diff two CSV files with different row order?
Pick a key column (like an ID or email) and rows are matched by that key instead of position, so re-sorted or re-exported files still compare correctly without false differences.
Can I compare CSV files with different columns?
Yes. Columns are matched by header name, so files with extra, missing, or reordered columns can still be compared — differences in shared columns are highlighted and unmatched columns are flagged.
Can I compare large CSV files?
Comparison runs locally in browser memory. The practical limit and processing time depend on your device, browser, row count, column count, and chosen matching mode.
Can I export the comparison result?
Yes, you can download a diff report listing every added, removed, and changed row for documentation, review, or audit trails.
Is my data private when comparing CSV files?
Completely. Both files are processed in your browser and never uploaded, stored, or logged — safe for sensitive data.
Is CSV Compare free to use?
Yes — free with no signup and no watermarks.
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