A small tool for a clearer picture
Two files.
Know what changed.
Compare an old export with a new one. Find the rows that were added, removed or changed — without uploading either file.
Choose your two files
Use UTF-8 files with column names in the first row. Up to 5 MiB per file, 50,000 rows, 200 columns and 1,000,000 cells.
Choose a file above, or drop it here.
Choose a file above, or drop it here.
Your comparison
Here’s what changed.
| Change | Key | What changed | Inspect values |
|---|
No keys match this view. Try another search or filter.
The report includes all differences, regardless of the current view. It uses one row per changed field, plus every field of added or removed rows. Formula-like values get a leading apostrophe to help prevent spreadsheet execution. Report exports are limited to 25 million characters.
Small details, fewer surprises
A comparison
you can follow.
How are rows matched?
The selected key must exist in both files. Every key must be nonempty and unique within its own file. Duplicate keys stop the comparison, with the affected data rows identified. Row order and column order don’t matter.
Values are compared exactly, including case, spaces and leading zeroes. Header names have surrounding spaces removed. Blank lines are ignored. A missing column is different from an empty value.
What’s in the CSV report?
Each report row contains a change type, key, column, before value and after value, followed by presence flags and data row numbers. A presence flag is false when the row or column did not exist in that file. Data row 1 means the first row after the header.
Cells beginning with formula-like content are prefixed with an apostrophe. This protection intentionally changes those exported strings; the on-screen comparison still uses the original values. A report for identical data contains its header only. Column changes are also shown above the table, even when both files have no data rows.
Long values may be shortened on screen at 2,000 characters. The report retains their full contents. Spreadsheet behavior varies, so review unfamiliar content before opening it.
Where do my files go?
They stay in this browser tab. This tool reads files you choose and creates the report here, with no uploads, analytics, account, saved history or external libraries. Reset clears the tool’s selected files and results. The page itself makes no network requests after its own files load.
You can download the tool and open its index.html file locally, even without an internet connection.
Which files work?
Choose a UTF-8 CSV with comma, semicolon or tab separators. Quoted separators, escaped quotation marks, multiline fields, and a UTF-8 byte-order mark are supported. Each row must have the same number of fields as its header.
Limits per file: 5 MiB, 50,000 data rows, 200 columns, and 1,000,000 cells including the header. Excel workbooks and other text encodings must first be exported as UTF-8 CSV.