Dzzz

Compare two CSV or Excel files

On-device

See what changed between two CSV/Excel files

A
B

Compare two CSV, TSV, XLSX or JSON files by a shared key column, right on your device — see rows that were added, removed or changed, and export the diff as a CSV. Nothing is uploaded.

Not sure which CSV tool you need? See all six →

About this tool

What you provide

  • Two CSV, TSV, XLSX or JSON files, A and B.
  • A key column that exists in both files.

What you get

  • How many rows were added, removed and changed.
  • A diff.csv download holding those rows, each tagged added, removed or changed.

Limits

  • Both files need a shared key column; rows are matched by its value, not by their position.
  • If a key value appears more than once in a file, the in-page comparison keeps only the last row carrying it; on the big-file engine every matching pair is examined and the key is still counted once.
  • CSV and TSV files have no size limit: past 25 MB the tool offers an on-device database engine that reads them from disk, downloaded once (about 7 MB) and kept on your device. Excel and JSON files are still limited to 25 MB each, and only the first sheet of an Excel workbook is read.

How to use it

  1. Choose both files

    Pick the older version in the box marked A and the newer one in the box marked B.

  2. Pick the key column

    The "Key column" menu lists only the headers both files share — choose the one that identifies a row, such as an ID or email.

  3. Run the comparison

    Tap "Compare" to get counts of rows Added, Removed and Changed between the two files.

  4. Export the diff

    Tap "Export diff (CSV)" to save one file listing those rows with a "change" column marking each as added, removed or changed.

Frequently asked questions

How do I compare two CSV files to see what changed?

Upload the two CSV or Excel files you want to compare to the Compare CSV tool, and it shows you the differences between them.

Can I compare an Excel file against a CSV file?

Yes, the tool accepts CSV or Excel files for either side of the comparison.

Is my data uploaded to compare two files?

No, the comparison runs on your device, so your files stay on your device.