CSV Diff

1. Enter or paste the first table in List A.
2. Enter or paste the second table in List B, or use Upload for either list.
3. Choose a value in Delimiter, or keep Auto-detect.
4. Set First row is a header and enter Key column(s) when rows need key-based matching.
5. Check the counts, then inspect Added rows, Removed rows, and Changed rows.

Set the delimiter and row matching

Delimiter has Auto-detect, Comma ( , ), Semicolon ( ; ), Tab, Pipe ( | ), and Custom.... Auto-detect checks the first 25 lines of each input, skips empty lines in that range, and can detect a different delimiter for List A and List B. Custom delimiter accepts one character; an empty value uses a comma.

Turn on First row is a header when the first row contains column names. In Key column(s), enter comma-separated header names or 1-based column numbers, such as id or 1. Leave the field empty to match row 1 with row 1, row 2 with row 2, and so on.

If a requested key cannot be resolved in both tables, CSV Diff reports the problem and uses row position. Duplicate keys are matched in their order of appearance, and the results show a warning.

Change what counts as equal

Each policy changes what counts as an equal cell:

• Ignore case treats Alice and alice as equal.
• Ignore leading/trailing and extra whitespace trims values and collapses repeated internal whitespace.
• Numeric-aware comparison treats numeric text such as 5 and 5.0 as equal when both cells parse as numbers.
• Ignore column order (match by header name) compares matching header names, but only when both inputs have headers. Without headers, columns stay positional.

For example:

List A: id,name,city
1,Alice,London

List B: id,name,city
1,Alice,Berlin

Changed cells: city, London -> Berlin

Columns found in only one table appear under Column differences and are skipped when changed cells are compared. Uneven rows still produce a result, so inspect the counts and column notes when source rows have different shapes.

Use CSV Diff with exports and TSV data

Compare two exports with id in Key column(s), then inspect changed cells before loading the modified file into a reporting workflow.

For a generated CSV and an earlier run, use row position when both files keep the same order. Use Key column(s) when records can move.

For a TSV saved by another system, turn on Ignore column order (match by header name) to separate column rearrangement from value changes.

Export the diff report

After the comparison updates, choose Export CSV or Export JSON. The CSV export has status, row numbers, keys, changed columns, and before-and-after values. The JSON export has statistics, keys, row numbers, and changed-cell details. Added and removed entries do not include complete source-row contents.

The visible Added rows and Removed rows tables show the first 500 records. Changed rows shows the first 500 changed row groups, while the counts use the complete computed result.

Choose between CSV Diff and Spreadsheet Diff

Browse Spreadsheet Compare Tools for related comparison pages. Choose Spreadsheet Diff when the source is an .xlsx, .xlsm, .xls, .xlsb, or .ods workbook and you need sheet-by-sheet comparison, formulas, displayed values, or optional cell formatting.

CSV Diff reads selected files with FileReader, parses and compares them in the browser, and creates the report downloads locally.

Questions about CSV Diff