Three straightforward steps
- Choose or paste the input requested by this tool.
- Configure the options and run the operation locally.
- Review and download or copy the result.
Data TOOL
CSV Compare
Compare two CSV files by a key column and export added, removed and changed rows.
ON-DEVICESelected input is processed in this browser.
Loading tool…
The selected input stays under your control
On-device processing means the input is handled by browser APIs on the device running this page. Closing or refreshing the page normally clears the active in-memory working session.
Read the Privacy Policy →Compare two CSV versions using a stable key
Identify added, removed and changed records without comparing row positions blindly.
How to use it
- Load the earlier and later CSV files.
- Choose a unique key column present in both.
- Review and export added, removed and changed rows.
Supported input
- Two CSV files with compatible headers
- A stable key such as order_id or email
Worked example
Compare yesterday’s and today’s inventory exports by SKU to find new products and quantity changes.
Limitations
- Duplicate key values create ambiguous matches.
- Renamed columns need normalization before comparison.
Troubleshooting
- Deduplicate the key column in both files first.
- Clean headers when the same column has spacing or case differences.
Tool-specific questions
Does row order matter?
No, key-based comparison matches records by the chosen identifier.
Can it merge the files?
It reports differences; it does not automatically resolve them.
Before you process
Can I use this csv compare online without uploading my input?
Yes. This tool is labelled On-device, so the selected input is processed in your browser and is not sent to a ForgeMyFile processing API.
What happens if the browser cannot process it?
The tool shows a readable error and stops. It does not silently fall back to a cloud upload.
Why can performance differ between devices?
The browser is doing the work locally, so speed and practical file size depend on available memory, CPU and browser capabilities.