Change Diff

Compares this workbook against an earlier saved copy and tells you what changed — formulas first. Its headline finding is the one Excel cannot show you: a formula somebody replaced with a typed number.

Support

Email support@appgarden.co.uk. Include the Excel platform you are on (Windows, Mac or the web) and what the pane showed. If a comparison came out wrong, the two versions are the most useful thing you can send — but only send data you are content to share, and read the privacy notice first.

Replies are best-effort, usually within a few working days. There is no phone line.

Using it

Open the version you want to check, then Home › What changed. The pane is three steps in one column:

1. Choose the earlier file. Any .xlsx — last week's copy, a version downloaded out of OneDrive's history, the one you were emailed. It is read on your machine and uploaded nowhere. The workbook you have open is treated as the later version.
2. Say what to compare. Whole workbook or just this sheet; whether to include values that changed and formatting. Formula changes are always reported.
3. Compare. Read the headline, walk the list cell by cell, and write the report as a new set of sheets if you need to send it on.

The four classes, and why they are not equal

Every other comparison tool reports "these cells differ" and leaves you to work out which of the fourteen matter. This one separates them, and the order is the point:

• A formula replaced by a value. =SUM(B2:B9) is now 4823. The workbook still calculates, still looks right, and that number will never update again. Nothing in Excel flags it and no amount of staring at the current file reveals it — the evidence only exists in the difference from yesterday's.
• A formula that changed. =B2*1.15 is now =B2*1.2.
• A value that changed. An input moved from 100 to 120. Usually the edit somebody meant to make.
• Formatting only. Bold, a fill, a number format. Off by default, because it is not a change to a model.

Cells that merely recalculated — the same formula, a different answer, because something upstream moved — are counted but not listed. They are the consequence of the edit, and listing them buries the edit under its own fallout.

Inserted rows do not break it

Insert one row at the top of a five-thousand-row sheet and a positional comparison reports five thousand differences. This one reports one insertion. Formulas are compared in R1C1 terms — the form that does not change when a formula moves — and the two sheets are aligned before a single cell is compared. Microsoft's own Spreadsheet Compare and Inquire both fall over here, and it is the main reason this exists.

Structure

Inserted and deleted rows and columns, sheets added, removed, renamed or reordered, and defined names that were repointed. That last one is the sneakiest change Excel allows: move what Uplift refers to and every formula using it means something else, without one character of formula text changing anywhere.

What you get back

Four sheets, written fresh. Neither version is modified.

• Summary — the count per class, with the critical one stated as a sentence.
• Changes — one row per change: sheet, both cell addresses, before, after, and both formula forms. Sorted by severity.
• Structure — inserted and deleted rows, sheet-level changes, defined-name changes.
• Audit — both file names, both timestamps, sheet counts, the version, the run time and every option that was on. This is the answer to "how did you produce this" when you are not in the room.

Walking the changes in place

The pane lists the findings and takes you to each cell in the workbook, in context, with its neighbours around it. It selects and scrolls; it does not colour anything in. One of these two files is evidence and the other is your live work, and an add-in that marked up either has damaged the thing you were trying to inspect.

Free and paid

Free compares the active sheet, up to 1,000 rows, and reports the two formula classes — enough to prove the alignment works on your own model, not enough to review a quarter's changes with.

Pro adds the whole workbook, every change class, structural detection, the report export and in-workbook navigation — £5 a month or £45 a year. Prices and checkout.

Paddle is the merchant of record and takes the payment. The terms of service, the refund policy — a full refund within 30 days of any payment — and the privacy notice set out the rest.

Your licence key

Keys are shown on screen at the end of checkout, not emailed. Keep the page, or paste the key straight into the pane. Lost it? Email support with the address you paid on.

Entering the key stores an entitlement on that machine. If Office clears its storage — which it does on the web, and Safari does on its own — re-entering the same key does not cost you a seat.

Known limits

• The earlier version has to be a file you can pick. Excel's add-in API can only see the workbook hosting the pane, so the other version is read from disk. Download it out of OneDrive or SharePoint version history first if that is where it lives.
• Volatile formulas are compared on their text, not their result. TODAY() and RAND() return something different every time the file opens; treating that as a change would fill every report with edits nobody made.
• Dynamic arrays are read from their anchor cell. A spill's other cells hold values, not formulas, and are marked as such so they are never reported as a formula that became a number. A two-dimensional spill's interior is not always recognised, which errs towards reporting a real change rather than hiding one.
• Localised function names are not translated. A file saved by an Excel that writes SUMME and one that writes SUM will compare as different. Separators and spacing are normalised; function names are not.
• Conditional formatting, data validation and table ranges are not compared yet. Those are logic, not formatting, and they are on the list rather than folded into the formatting class.
• This is not a merge tool. It reports; it never writes changes from one version into the other. That is a different product with a different risk profile.
• Excel on Mac and on iPad are untested. The manifest permits them, so Microsoft lists them, but no verification run has happened on either. Please report anything that misbehaves.