Compare two spreadsheets privately. Your data never leaves your browser.
No. Both files are read and compared entirely inside your browser using JavaScript. Nothing is sent to a server, so confidential spreadsheets stay on your device.
Free comparisons support up to 5,000 rows per file. Pro removes the cap, limited only by your browser's memory. The comparison runs in a background thread so the page stays responsive on large files.
If a key value appears more than once in either file, those rows are not silently dropped or guessed at. They are excluded from the match and listed in a separate Duplicate Keys section so you can review them.
Excel (.xlsx and .xls) and CSV files. You can compare an Excel file against a CSV, and choose a sheet when a workbook has several.