Why your books don't match your bank, and how to find the difference
A reconciliation difference is not a mystery. There are five things it can be, and each one leaves a trace you can follow in an afternoon.
A bank reconciliation is two independent records of the same money. The books say one number, the bank says another, and the point of the exercise is not to make them agree — it is to find out why they do not. The difference is the finding.
Almost every difference in a small set of books is one of five things. Work down them in order and you will usually have your answer before you have finished the list.
1. Transactions the bank has and the books do not
The commonest by a distance. A statement line was imported and never coded, or never imported at all. Add up the unreconciled lines: if that total equals your difference, you are done.
2. Transactions the books have and the bank does not
A cheque written but not yet presented, or a payment recorded on the day it was authorised rather than the day it cleared. These are legitimate and will resolve themselves; what matters is that they are visible rather than absorbed into a single balance.
3. The opening balance is wrong
This one is worth its own paragraph because it hides so well. If your books were anchored to a balance on one date and you later imported statements from before that date, every one of those earlier transactions is counted twice — once inside the opening balance, which already contained them, and once as itself.
How to spot it
Add up every transaction dated before your conversion date. If that total is exactly your difference, this is your answer, and the fix is to move the conversion date back rather than to reverse four hundred entries.
4. The same transaction imported twice
Two statements that overlap by a few days, or the same file uploaded twice. A good import deduplicates on the bank's own transaction id where the format carries one, and on a hash of the date, amount and description where it does not — but an overlap of legitimately identical lines, two identical coffees on one day, has to survive that.
5. Something was edited after it was reconciled
Which is why posted entries should not be editable at all. A correction belongs in a reversal, so the original and the correction both remain visible and the audit trail reads as what happened rather than as what somebody wishes had happened.
Doing it in APX Ledger
The bank tile on the dashboard shows the books' balance beside the bank's own last word and the difference between them. It is not presented as an error, because cheques not yet cleared produce one legitimately — but it has a number, and the number links to the transactions on either side of it.
A balance you have to trust is worse than a difference you can explain.