Why VCC
A spreadsheet is not evidence.
When a number is worth money, someone will eventually ask where it came from. VCC exists for that moment: it turns a calculation into portable calculation evidence — a receipt the other side can check for themselves, instead of a file they have to take on faith.
The dispute starts the same way, every time.
A customer contests a commission payout. A policyholder questions an insurance premium. A counterparty pushes back on a quote. The other side wants one thing — show me how you got this number — and on your side, a manual hunt begins:
- Which spreadsheet?
- Which version?
- Which formula?
- Which rounding?
- Which price list?
Days pass. Emails multiply. And the honest answer, most of the time, is the same:
The number exists.
Its provenance does not.
VCC was built for exactly that gap. Not a better calculator — the math was never the problem — but evidence that travels with the number: which rule ran, at which version, on which inputs, producing which result. Recorded once, at the moment of calculation, and checkable by anyone, years later.
Three tests
Three questions to ask about any number you produce.
Does this number need a VCC?
Not every calculation deserves a receipt. Run one number through four questions:
- Are two parties involved?
- Is money at stake?
- Is the formula agreed in a contract, plan or policy?
- Might someone dispute it later?
Two or more yes — that number needs evidence, not a promise. One or none — a spreadsheet is probably fine. Most numbers never get questioned; the ones that do are exactly the ones you least want to defend from memory.
How expensive is an unprovable calculation?
The cost is never the number itself — it is what happens every time the number cannot defend itself. Industry research on sales compensation, one of the most disputed calculation domains, puts figures on it:
60%+
of sales reps ran into a commission error in the last 12 months.
42%
of salespeople have left a job over a compensation dispute.
25–50%
of a rep's month can go into shadow accounting — rebuilding the official number in a private spreadsheet, because the official one can't be trusted.
Figures from published industry research on sales compensation. Your domain will have different numbers — the pattern of hours, disputes and lost trust will not.
Could you reproduce this number in two years?
Take one number you produced today and ask whether — after the analyst has left and the file has been renamed twice — you could reproduce it exactly. Not approximately. Byte for byte.
A spreadsheet
The file has copies, the formula may have been edited since, the inputs are cells anyone can overwrite, and the rounding lives in cell formatting. Reproducing the number means reconstructing it — and hoping the reconstruction matches.
A VCC receipt
The formula is versioned and pinned by digest, the inputs are recorded, the output is signed. Re-check it offline any time and, when the formula resolves, re-run it — the same bytes, two years later.
What a VCC receipt actually does.
- It records which formula ran, at which version, on which inputs — and which result came out.
- It is signed and content-addressed, so nothing can change after the fact.
- Anyone can check it later, offline, without trusting us or this site.
Under the hood, VCC is an experimental open protocol — the format, the numeric rules and the threat model are public. Read the specification