Bookkeeping · Reconciliation & Close · Brief · Working level
Discrepancy hunting: finding reconciliation differences fast
A fixed diagnostic order for tracking down a reconciliation difference — interrogate the number first, then the entries — including the divisible-by-9 and halving tricks.
A reconciliation that will not balance is not a search problem; it is an interrogation problem. The difference itself — its exact amount, its arithmetic properties, its history — usually names the error before you re-tick a single line. Work the diagnostics in order of how often each cause occurs, and most differences fall inside ten minutes.
The diagnostic order
- Fix the starting point first. Confirm the opening balance equals last period's reconciled closing balance. If not, this month's error is last month's — stop and repair upstream, per opening balance problems.
- Search for the exact difference. Search both the statement and the ledger for the precise amount. A hit means an item ticked twice, missed entirely, or entered twice.
- Halve it and search again. A wrong-side posting doubles its own footprint. Difference of 620.00 → hunt for 310.00.
- Divide by 9. Clean division suggests a transposition (541 → 514, difference 27) or a decimal slide (541.00 → 54.10, difference 486.90 — also divisible by 9). Scan recent manual entries for candidate digits.
- Count items, not just dollars. Compare transaction counts per side; a count mismatch localizes a missing item faster than amounts do.
- Check the fringes. First and last days of the period — cutoff errors — and any transfers between your own accounts, which must appear once on each side and often appear twice on one.
- Only then re-tick, in one direction at a time, marking as you go.
Reading the number
What the difference's signature usually means:
| Signature | Likely cause | Move |
|---|---|---|
| Equals one transaction exactly | Missed or duplicated item | Search both sides for the amount |
| Exactly double a transaction | Debit/credit reversed | Halve, then search |
| Divisible by 9 | Transposed digits or decimal slide | Scan manual entries |
| Round (50.00, 100.00) | Keystroke or estimate error | Compare entries to source documents |
| Same as last month | Prior reconciliation forced or unfinished | Repair the prior period first |
| Tiny and constant (0.01–0.05) | Rounding in an import or conversion | Write it off deliberately, with a memo |
The two tricks earn a worked example each. Divisible by 9: your difference is 270.00, and 270 ÷ 9 = 30, so a transposition is possible — scanning recent entries turns up a deposit of 3,410.00 keyed as 3,140.00, a swap of the middle digits producing exactly 270.00. Note that the test is a screen, not a proof: confirm against the source document before "fixing" anything, because unrelated errors can also happen to divide by 9. Halving: a difference of 178.00 halves to 89.00, and there in the ledger is an 89.00 refund entered as a payment. Reverse it and the reconciliation lands.
Preventing the next hunt
Most hunts trace to the same few habits: manual keying instead of importing, transfers entered on one side only, and reconciliations done quarterly instead of monthly — a 90-day haystack instead of a 30-day one. The cadence case is made in the reconciliation frequency guide, and the full procedure these diagnostics plug into is the bank reconciliation guide.
Frequently asked questions
- How do I find the difference when a reconciliation won't balance?
- Interrogate the exact difference before re-checking anything: search both sides for that precise amount (a missed or doubled item), halve it and search again (an item on the wrong side), and test divisibility by 9 (a transposition or decimal slide). Only if the number tells you nothing do you fall back to line-by-line re-ticking.
- Why does dividing a difference by 9 find transposition errors?
- Because the difference between any number and a rearrangement of its digits is always a multiple of 9 — 541 entered as 514 creates a difference of 27. A decimal slide (541.00 entered as 54.10) is likewise divisible by 9. So when a reconciliation difference divides evenly by 9, scan recent entries for swapped digits or a shifted decimal.
- What does it mean when the difference is exactly double a transaction?
- An amount posted to the wrong side — a debit entered as a credit or vice versa — throws the reconciliation off by twice the amount, since the correct side is missing it and the wrong side carries it. Halve the difference and search both records for that figure; wrong-side postings are among the most common reconciliation errors.