CSV Compare
Compare two CSV files and see which rows were added, removed, or changed. Pick the column that identifies each row (like an ID), and the tool shows every difference. Your data never leaves your browser.
1. Add your two CSV files
2. Options
Key columns (they identify the same row in both files)
3. Results
How to compare two CSV files
- Paste or choose your original CSV in File A and your updated CSV in File B.
- Tick the key column (or columns) that identify each row, such as an ID or email.
- Click Compare.
- Open the Changed, Removed, and Added tabs, or download the full report.
Frequently asked questions
Are my files uploaded anywhere?
No. The comparison runs entirely in your browser. Nothing is sent to a server.
What is a key column?
A key column holds a value that is unique for each row, like an employee ID. The tool uses it to match a row in File A with the same row in File B, even if the rows are in a different order.
What if I have no unique column?
Tick the option to compare by row position, or tick several key columns together (for example first name and last name) so the combination is unique.
What do Added, Removed, and Changed mean?
Removed rows exist only in File A. Added rows exist only in File B. Changed rows exist in both files but have different values in one or more columns.
What if the files have different columns?
Only columns that exist in both files are compared. The tool tells you which columns appear in only one file.
What if a key appears more than once?
Duplicate keys are matched in order: the first match in A is compared with the first match in B, the second with the second, and so on. The tool shows a warning so you can check your key choice.
Is there a size limit?
There is no fixed limit, but very large files (hundreds of thousands of rows) may be slow because everything is processed on your device. The screen shows the first 500 rows of each list, and the downloaded report contains all differences.