Compare two Excel files — without uploading them

Drop in two versions of a spreadsheet and see exactly which rows were added, removed, or changed — matched by ID, with cosmetic formatting differences filtered out. Works with .xlsx, .xlsm and .csv.

✓ 100% in your browser — your files never leave your computer

How it works

1. Pick the two files. The older version goes on the left, the newer on the right. Only the first sheet of each workbook is compared.
2. Choose the column that identifies a row — an invoice number, employee ID, SKU. We suggest the most identifier-like column automatically. Rows are matched by that value, so re-sorted files compare correctly.
3. Read the differences. Rows present only in the new file are added, rows present only in the old file are removed, and matched rows with different values are changed, listed field by field.

What counts as a change?

Comparison is type-aware: 1,200.00 and 1200 are the same amount, and 01/03/2024 is the same day as 2024-03-01, so pure formatting differences don't drown out the real ones. Rows with a duplicated or blank ID can't be matched reliably — the tool tells you about them instead of guessing.

Is anything uploaded?

No. The files are read with your browser's own file APIs and compared by JavaScript running on your machine. There is no server to upload to — this page ships with a Content-Security-Policy that makes your browser block outbound requests. Here's how to verify that yourself, including with your Wi-Fi off.

How big can the files be?

Tested to 500,000 rows / 38 MB per file on an ordinary laptop — see the published benchmark. Everything runs on a background thread, so the page stays responsive while big files parse.

← Prism — the review step before you trust the file