Guide

How to sign off a calculation so that a red verification means something, and a green one means what you think it means.

Before you sign: mark the input cells

This is the one decision that matters, and it is worth two minutes. Input cells are the ones people are expected to type into: a flow rate, a discount percentage, a date. Everything else — every formula, and every constant outside those cells — becomes part of the calculation's fingerprint.

Open Input cells in the pane, select a range in the sheet, and press Add the selected cells. Repeat for each block. The designation is stored in the workbook, so it travels with the file and the next person to sign it gets the same answer you did.

Get it wrong in either direction and the product misbehaves in a way that looks like a bug:

• Too narrow — somebody enters a value the way the calculation intends, and the record turns red. Reds nobody believes are reds nobody reads.
• Too wide — a "input" area big enough to hide an edited constant in. Widening the designation is itself a change to the fingerprint, so it cannot be done quietly after signing, but it can be done wrong before.

A formula sitting inside an input range is always treated as logic, and the checks flag it (CS-06). That is the one case where the two rules could have left a hole.

The pre-sign checks

None of these stops you signing. Your judgement is the point of a sign-off. What the checks found is recorded on the record itself, so a recipient can see that you signed a calculation with eleven hardcoded values in it — which is a different statement from signing a clean one.

There is one thing the add-in refuses to sign: a workbook it could not read in full. A fingerprint taken over part of a file verifies green while saying nothing about the rest, and that is the most dangerous output this product could produce.

Signing

Type your name, pick Prepared, Checked or Approved, add a revision and a comment, and press Sign. Three tick boxes control what else happens:

• Protect the calculation — locks every cell except your input ranges, and turns sheet protection on. An existing filter still works, so a checker can narrow a table down to read it. Sorting does not: Excel only allows a sort of cells that are unlocked, and a signed calculation is locked. Unlock what you need before signing, or sort first and sign after.
• Write a printable Sign-off sheet — a page for the quality file, with the whole chain on it.
• Countersign with App Garden — the server signs the record hash, which is what stops the record itself being edited afterwards.

Prepared, Checked, Approved

Sign a workbook more than once and the records chain: each one carries the hash of the one before it. Remove or reorder an entry and the chain stops holding, and the pane says so. That is the ISO 9001 design-assurance workflow — three signatures in order, not three independent stamps.

Reading a verification

Green

Logic unchanged since J. Smith, Checked, 10 September 2026, Rev B. The formulas, the constants outside your input cells, the names and the sheet structure are exactly as signed. If the inputs have changed, it says so separately — that is normal use, not an error.

Red

14 changes to the calculation since it was signed, with each cell listed, what it holds now, and what it held at signing. A red is never allowed to be just "tampered": a verification that accuses somebody without naming a cell is worse than no verification.

Amber

Amber is the one worth understanding. It means not checked, and it is never a pass:

• No sign-off present — the file carries no record. That is not the same as unchanged; a record can be deleted.
• Signed under a different fingerprint version — an older or newer add-in. The file has not been shown to have changed.
• The record itself does not verify — the calculation matches, but the record has been altered since it was issued: a changed name, date or revision.
• The workbook could not be read in full — a sheet too large to read in one pass.

What the fingerprint covers

In it: every formula (as R1C1, so inserting a row is not an edit); every constant outside the input cells; defined names and their formulas; the sheet list, its order, and which sheets are hidden; each sheet's used range; and the input designation itself.

Not in it: number formats, fonts, colours and column widths; comments and notes; calculation mode; anything inside a linked workbook; charts, images and shapes.

So changing a number format does not turn a record red, and you are entitled to know that before you rely on it.

The free tier

Verifying is unlimited and always will be. Signing is three local records a month, marked "not countersigned" on their face. The pre-sign checks, the lock, the printable sheet, the export and the countersignature are Pro.