CSV or Excel tool
Compare CSV Files
Compare two CSV files and see which rows were added, removed or changed. Match rows by a key column, or compare whole rows when there is no key.
Add files
Drop CSV files here, or choose files. Everything stays on this device.
Waiting for files
Accepted input
- Exactly two CSV or TSV files
Limits
- Up to 20 MB per CSV/Excel file and up to 100000 rows.
- CSV, TSV, XLSX and JSON inputs are supported in this category.
Local processing
- Files are read in your browser and are never uploaded to a server.
- Nothing is stored after you close or reload the page.
How to use Compare CSV Files
- Add the first CSV as the "before" file and the second as the "after" file.
- Choose Key or Row mode and, in key mode, the zero-based key column.
- Press Compare CSV files and download the added, removed and changed row files.
What it does
- Reports added, removed and changed rows as separate downloadable CSV files.
- Key mode matches rows by one or more columns and lists the changed fields.
- Row mode compares whole rows, so column reordering does not create false changes.
Limits and things to know
- The header union is used for output; a column present in only one file is empty in the other side.
- Duplicate keys are rejected in key mode unless you compare by row instead.
- Only two files are compared per run.
Example
Checking a system export overnight
Compare before.csv and after.csv by key column 0. The tool writes added-rows.csv, removed-rows.csv, changed-rows.csv and a cell-changes.csv listing each field that differs.
Frequently asked questions
What if a key appears twice?
Key mode reports the duplicate and stops, because it cannot tell which row is the match. Use Row mode or fix the duplicate keys first.
Does column order matter?
No. Columns are matched by name, so reordering columns between files does not produce false differences.
Which file is before and which is after?
The first file you add is the before side and the second is after. Added rows exist only in the second file; removed rows exist only in the first.
Runs entirely in your browser on ap98.com. Files are never uploaded.