Benford & round numbers
Two cheap tests over a pasted column. Neither proves anything; both tell you where to look.
- Runs
- In this tab
- Data sent
- None
- Rounding
- Once, at the end
- Also in
- The Chrome extension
Benford & round numbers, worked
Showing a worked example — type over it
Result
How the benford & round numbers works.
Benford's law: First-digit distribution with a χ² result over a pasted column.
Round-number test: Concentration at .00 / .50 / 000 — the other cheap fraud smell.
Quoted from the toolbelt spec, the document this tool was built against.
Where these numbers come from.
Negatives are parenthesised because that is what a statement does. The rest is four promises.
Minor units, never floats
Amounts are integers in the currency's smallest unit, end to end. A float never touches a cent.
Rounded once
Rounded once, at the end — never per operand, which is how a split stops summing to the whole.
Unit tested
The arithmetic lives in one unit-tested module, shared without reimplementation with the extension.
No network
There is no request to make. What you type stays in this tab and is gone when you close it.
More in reconciliation & investigation
- Difference diagnoserOut by 8,100? That is divisible by 9 — a transposition. This says which error fits the gap.
- Which invoices make this deposit?A deposit against forty open items. Exact subset-sum over minor units — no floating point.
- Two-list matcherBank against ledger: exact, then reference, then a date window, then one-to-many — and what is left on both sides.
- Duplicate paymentsSame vendor, same amount, close in time — plus the same reference whatever the date.
Read it in context
- Founder guide · 7 minBad debt and write-offs: allowance vs direct methodHow to book a customer who won’t pay: the GAAP allowance under ASC 326, the direct write-off the IRS requires, and what to do if the money comes back.
- Founder guide · 4 minAudit-ready books before your Series AInvestors, lenders and auditors ask for the same things: accrual statements, reconciled accounts and support for every balance. How to be ready first.
- Founder guide · 3 minCan you vibe code your startup’s accounting?AI coding tools build a finance dashboard in an afternoon, but not a closed, reconciled, GAAP-basis ledger. Where the line is, and how to stay inside it.
The same number, elsewhere.
A calculator answers the question once. These carry the answer into a product, name what it computed, and argue the method.
- ComponentIntegrityCheckPanelEleven continuous assertions. A failure owns the screen.
- ComponentSamplingToolMethod and seed recorded — reproducible selection.
- ComponentAnomalyCardA flagged deviation with its explanation.
- TermMaterialityWhether a misstatement or omission would likely change the judgment of a reasonable user of the statements — judged on size and nature together, never a fixed percentage
- TermEvidenceDocumentation supporting a recorded amount
- TermFindingAn identified control or accounting problem
- DocControls & auditAccounting software is not a database with forms on top. It is a system of controls, and the UI is where most of those controls are actually enforced.
- DocCurrency decimal placesHow many decimals each ISO 4217 code is stored at — JPY 0, USD 2, KWD 3.