Upload your original CSV on the left and the updated version on the right, then click Find Differences. Changed cells highlight in yellow with the old value in parentheses. Added rows are green, removed rows are red. No external library needed - all processing runs in your browser instantly.
How to use this tool
Drop your original CSV file into the left panel and the updated version into the right panel. Click "Find Differences." The diff table appears below showing every row classified as changed, added, removed, or unchanged.
Use the Sample button to load a small example dataset and see how the output looks before uploading your own files. The Swap button exchanges both files without re-uploading. Copy Diff copies the entire result as tab-separated text.
CSV vs Excel comparison tool
This site has two spreadsheet comparison tools. Here is when to use each:
| Scenario | Use this tool | Use Excel tool |
|---|---|---|
| Pure .csv or .txt files | ✓ Faster, no CDN load | Also works |
| .xlsx, .xls, .ods files | Not supported | ✓ Required |
| Multi-sheet workbooks | Not applicable | ✓ Sheet tabs |
| Low bandwidth / fast load | ✓ No dependencies | Loads SheetJS (~1 MB) |
Use cases
Database and API export verification
Most databases and web APIs can export data as CSV. Compare two exports taken at different times to see exactly which records were added, removed, or changed - without writing custom scripts or loading data into a spreadsheet application.
ETL pipeline validation
After running an extract-transform-load pipeline, compare the input CSV against the output CSV to verify that the transformation applied correctly. Any unexpected cell changes immediately surface in the diff.
Configuration and seed data changes
Many applications store seed data, reference tables, or feature flags in CSV files. Comparing two versions of a seed file before deploying confirms exactly which rows and values changed, giving you an auditable diff for the deployment record.
How the comparison works
The tool uses a built-in CSV parser - no external libraries are loaded. The parser handles quoted fields (including commas inside quoted strings) and escaped double-quotes per the RFC 4180 standard. Rows are matched positionally: row N in the original is compared to row N in the changed file. Within each row, cells are compared as strings after trimming whitespace.
FAQs
How do I compare two CSV files online?
Upload your original CSV on the left and the updated CSV on the right, then click Find Differences. The diff table shows every changed cell in yellow, added rows in green, and removed rows in red.
Does this handle quoted CSV fields?
Yes. The parser handles quoted fields that contain commas, newlines, or double quotes per the RFC 4180 CSV standard.
Is my data safe?
Yes. No file is uploaded to any server. All parsing and comparison runs in your browser using JavaScript.
Can I compare a CSV against an Excel file?
Not with this tool - it only accepts .csv and .txt files. Use the Excel & CSV comparison tool to compare across formats.