Compare two workbooks

We line up the two files sheet by sheet, then cell by cell — the same way you would if you put them side by side. A cell counts as unchanged only if everything about it is the same. Anything else is a change.

We compare what is stored, not what is displayed

Excel often shows you a tidied-up version of a value. We look at what is actually saved in the file.

The second one has a trailing space. On screen they look identical, so this is exactly the kind of thing worth catching.

Formulas are compared as text

Two formulas that give the same answer are still different formulas. We never recalculate anything.

Formatting counts too

If the number is the same but the cell was made bold, or the date format changed, we flag it.

An empty cell is not the same as no cell

If someone typed something and then deleted it, Excel remembers that the cell exists. We count that as a change from a cell that was never touched. Blank rows you never visited are ignored entirely — we only look at cells one of the two files actually stores.

Renaming a sheet reads as remove and add

We match sheets by name. If Sheet1 becomes Q1 Data, we report one sheet gone and one sheet arrived, rather than quietly assuming they are the same sheet. When the contents look almost the same, we add a note under Workbook settings suggesting the rename, with the percentage of cells that match.

Formatting applied to a whole row or column counts as well

If someone makes row 5 bold without touching the individual cells, every cell in that row is reported as changed. The report also tells you where each cell’s formatting came from — the cell itself, its row, or its column.

Charts, macros and the rest

A workbook carries much more than cells: conditional formatting rules, charts, pivot tables, macros, links to other files, digital signatures, images and more. For these we compare the underlying components and tell you whether each one is the same, changed, added or removed. We do not open a chart to judge whether it looks nicer, and macros are never run.

Proving a report has not been altered

Every report carries a result digest: a fingerprint calculated from the two workbooks, the software version and the headline findings. Anyone holding the same two files can run SpreadCheck again and get the same digest, so the finding can always be re-derived independently.

If this site is set up with a verification registry, the fingerprint of the PDF itself is also recorded when you export it. A reviewer can then drop the PDF into the verify page and be told whether it is byte-for-byte the file that was issued. Your workbooks are never sent anywhere - only fingerprints.

What we cannot do

Files up to 30 MB and about 1,000,000 stored cells per workbook, in .xlsx or .xlsm format only. Older .xls, .xlsb, CSV and password-protected files are not supported. Before using this for anything regulated, have it validated under your organisation’s own process.