Free · No upload · No Excel needed

Compare two .xlsx files in your browser

Drop an old workbook and a new one. SheetDelta reads the .xlsx format directly and shows every changed cell, formula, and sheet — with no Excel install and nothing sent to a server.

Compare files below Why .xlsx is special

Compare your .xlsx files here

Drop two workbooks. They’re read on your device — nothing is uploaded.

Old / Base file

.xlsx .xlsm .xls .xlsb

or click to browse

New / Modified file

.xlsx .xlsm .xls .xlsb

or click to browse

Files never leave your computer. All processing happens locally via WebAssembly.
Runs 100% in your browser. Your files never leave your computer.

Built for the .xlsx format

Reads the format directly

A .xlsx file is an Open XML package — a zip of XML parts. SheetDelta opens that package and reads the cells, so you don’t need Excel installed to compare two of them.

No Excel, no install

The comparison runs in your browser with WebAssembly. There’s nothing to download and no Office dependency, so it works the same on Windows, Mac, and Chromebook.

Cells and formulas

See every changed value and every changed formula, added cells, and deleted cells — highlighted in place instead of listed as “Sheet1!B7 differs”.

Inserted rows stay sane

Add one row near the top and a row-by-row compare flags everything below it. SheetDelta aligns the rows first, so an inserted row reads as a single addition.

Ignores save-only churn

Excel rewrites shared strings, the calc chain, and style numbering on every save. That noise is invisible to a plain file compare; SheetDelta filters it out.

Nothing uploaded

Both .xlsx files are read on your machine and never sent anywhere. There’s no server copy, so a confidential workbook stays where it is.

An .xlsx file is a zip of XML — that changes everything

Since Excel 2007, the default .xlsx extension has been Microsoft’s Open XML format. It isn’t one file so much as a small archive: rename a workbook to .zip, unzip it, and you’ll see XML parts for each sheet, a shared-strings table, a styles table, and more. That design has two consequences for comparing them.

First, the good news: because the contents are structured XML, a tool can read a workbook without Excel anywhere in sight. That’s why SheetDelta runs in a browser tab and never asks you to install Office.

Second, the catch: a plain “compare two files” utility sees only the compressed bytes, which differ wildly between two saves of the same workbook. Even unzipping won’t save you — Excel reorders the shared-strings table, reshuffles the calc chain, and renumbers styles on every save, so a text diff drowns in churn that has nothing to do with your numbers. A real diff has to understand the workbook, align the sheets and rows, and read formulas as logic. That’s the difference between “these files differ” and “the discount rate in Assumptions!B12 went from 8% to 9%”.

.xlsx vs .xls vs .xlsm

The extension tells you how the workbook is stored and what it can hold. Three you’ll meet most:

.xlsx — the modern default

Open XML, no macros. The everyday format for most workbooks today. This is what the free tool above compares.

.xlsm — macro-enabled

The same Open XML format, but allowed to carry VBA macros. The web tool compares its cells and formulas; comparing the macro code needs the desktop app or platform. See compare .xlsm files.

.xls — the legacy binary

Excel 2003 and earlier. A binary format, not XML, so it needs the full engine. Compare .xls and binary .xlsb with the desktop app.

Frequently asked questions

What is an .xlsx file, exactly?
.xlsx is the default Excel format since Excel 2007 — Microsoft’s Open XML (also called OOXML). Rename one to .zip and unzip it and you’ll find a folder of XML files describing the sheets, cells, and styles. That structure is why a tool can read a workbook without Excel, and why a plain text compare on the raw bytes is useless.
Do I need Excel installed to compare two .xlsx files?
No. SheetDelta reads the .xlsx package directly in your browser, so there’s no Excel, no Office, and no install required. Drop two files and read the result.
What’s the difference between .xlsx and .xls?
.xls is the old binary format from Excel 2003 and earlier; .xlsx is the modern XML-based one. The web tool compares .xlsx (and .xlsm). For legacy .xls and binary .xlsb, use the desktop app, which carries the full engine.
Can it compare macro-enabled workbooks (.xlsm)?
Yes for the cells and formulas — drop two .xlsm files and you’ll see every cell change. Comparing the macro code itself (the VBA) needs the desktop app, platform, or GitHub Action. See comparing .xlsm files and VBA diff.
Why does Windows’ file compare or a generic diff fail on .xlsx?
Because the file is a compressed archive, not text. A byte-level compare sees two zips that differ everywhere, and unzipping doesn’t help — you’d be diffing reordered shared strings and shuffled styles, not the numbers. You need a diff that understands the workbook inside.
Is there a file-size limit?
Everything runs locally, so the limit is your browser and machine rather than an upload cap. Very large workbooks are better handled by the desktop app, which uses the full engine.

More ways to compare

Compare Excel files →

Drop two workbooks and see every changed cell, formula, and sheet — free, in your browser.
Compare Excel sheets →

Match sheets and rows even after they move, so inserts don’t drown the real changes.
Excel diff →

A real diff for Excel — formula logic and structure, not a line-by-line text compare.
Compare .xlsm files →

See macro and formula changes in macro-enabled workbooks.

Comparing the same .xlsx every week?

Let SheetDelta watch your SharePoint or OneDrive, keep the version history, and route each change for review — so you stop re-running the comparison by hand.

See the platform Excel version control