Key takeaways
What this article covers, in order:
- Before the clock starts: write the difference down
- The 30-minute method
- Minutes 0 to 3: Is the opening balance right?
- Minutes 3 to 6: Search for the exact amount
- Minutes 6 to 10: Halve it
- Minutes 10 to 14: Divide by 9
You've matched everything you can, the adjusted balances still disagree, and the difference is sitting there on the screen: $546.40. Before you start rereading every line from the top, stop. Bank reconciliation not balancing? The cause is usually on a short list, and there are quick tests that point straight at it. Here's a timed method that finds the problem in under half an hour more often than not.
Before the clock starts: write the difference down
Note the exact difference and which side is higher. "Bank is $546.40 higher than books" is far more useful than "it's out by about five hundred". Direction matters. It tells you if you're hunting for money missing from your books, or money that shouldn't be there at all.
The 30-minute method
| Minutes | What you check | Why |
|---|---|---|
| 0 to 3 | Opening balance | If it's wrong, nothing else will fix it |
| 3 to 6 | Search for the exact difference | A single missing or extra item |
| 6 to 10 | Halve the difference and search | A sign reversed (in as out, or out as in) |
| 10 to 14 | Divide the difference by 9 | Swapped digits or a misplaced decimal point |
| 14 to 20 | Look for duplicates | Feed plus manual entry, or a double import |
| 20 to 25 | Check the cut-off dates | Items posted to the wrong month |
| 25 to 30 | Check the statement-only items | Fees, interest, direct debits not entered |
If you get to minute 30 with nothing, take a break. Fresh eyes find things tired ones don't.
Minutes 0 to 3: Is the opening balance right?
Compare your opening book balance for this period with the closing balance on last period's signed-off reconciliation. If someone edited, deleted or backdated a transaction in a month that was already reconciled, the opening balance shifts and this month inherits the problem.
If the opening balance is out by the same amount as your current difference, you've found it. The error is in a prior period, and that's where it needs to be fixed.
Minutes 3 to 6: Search for the exact amount
Search your books and your statement for the exact difference. If the bank is $546.40 higher, is there a $546.40 deposit on the statement that isn't in your books? Or a $546.40 payment in your books that isn't on the statement and isn't a genuine outstanding item?
One missing transaction is the single most common cause, so this search earns its three minutes.
Minutes 6 to 10: Halve it
If a transaction was entered with the wrong sign, say a refund you received entered as money you paid, the error is double the amount. Your books moved down when they should have moved up.
So halve the difference and search for that. $546.40 ÷ 2 = $273.20. Any $273.20 transactions around? If yes, check whether it's going the right way.
Minutes 10 to 14: Divide by 9
When two digits are swapped, say $3,620.00 typed as $3,260.00, the difference is always divisible by 9. Same with a slipped decimal point: $45.00 entered as $450.00 gives a difference of $405.00, which is 9 × $45.00.
Try it on the whole difference. $546.40 ÷ 9 = $60.71 and a bit. Not clean. Hold that thought, because sometimes there's more than one error stacked together.
Minutes 14 to 20: Hunt duplicates
Duplicates come from:
- a transaction entered by hand and then arriving again through the bank feed
- the same CSV statement imported twice
- a customer payment recorded against the invoice and again as a separate deposit
Sort your ledger by amount and look for pairs on the same or nearby dates. Recurring amounts like rent are legitimate pairs month to month, so focus on pairs within the same period.
Minutes 20 to 25: Check the cut-off
A payment made on 30 Sep 2026 but dated 1 Oct 2026 in your books (or the other way round) will throw out both months. Look at the first and last three days of the period on both the statement and the ledger.
Minutes 25 to 30: Check statement-only items
Fees, interest, dishonoured payments, direct debits. If any line on the statement still has no matching entry, it belongs in your books.
Worked example: Jordan's $546.40
Jordan runs a mobile mechanic business around Townsville. This is an illustrative example. He's reconciling September 2026 and the bank is $546.40 higher than his books.
Minutes 0 to 3. Opening balance agrees with his August 2026 reconciliation. Not that.
Minutes 3 to 6. No $546.40 anywhere. Not a single missing item.
Minutes 6 to 10. Half is $273.20. No transaction for that amount. Not a simple reversed sign.
Minutes 10 to 14. $546.40 doesn't divide cleanly by 9. But Jordan remembers that differences can stack, so he scans for any obviously suspicious amounts anyway. He spots a fleet customer's payment in his books for $3,260.00. The invoice was for $3,620.00, and the statement shows $3,620.00 arriving. Swapped digits. That's $360.00, and $360.00 ÷ 9 = $40.00. Clean.
He corrects the entry to $3,620.00. His books go up by $360.00. The remaining difference is $546.40 − $360.00 = $186.40.
Back to the halving test on the new difference: $186.40 ÷ 2 = $93.20. He searches for $93.20 and finds a parts supplier refund. The statement shows $93.20 coming in. His books show $93.20 going out, coded as a parts purchase. Reversing it to a receipt moves his books up by $93.20 × 2 = $186.40.
Difference now: $0.00. Total time: about 20 minutes.
| Error | Effect on books | Fix |
|---|---|---|
| $3,620.00 receipt entered as $3,260.00 | $360.00 too low | Correct the amount |
| $93.20 refund entered as a payment | $186.40 too low | Change it to money in |
| Total | $546.40 too low |
The lesson: when the whole difference doesn't pass a test, look for one error you can find, fix it, and run the tests again on what's left.
What if you still can't find it?
It happens. Some honest advice:
- Don't force it. Never post a random adjustment to "make it balance". You'll bury the real error and it'll surface somewhere worse later.
- Check the bank's figures too. Banks do occasionally make mistakes, like a duplicated direct debit or a deposit credited to the wrong account. If a line on the statement makes no sense, ring them.
- Go transaction by transaction for the period, ticking both sides. Slow, but it always works.
- Ask for help if a difference has been carried for more than one period. A bookkeeper or BAS agent who sees this every week will often spot it in minutes.
How HelloBooks helps
HelloBooks' reconcile screen does a lot of the matching for you: each statement line gets an AI match suggestion, a confidence score and a note on why it picked that match. That leaves you with only the exceptions, which is exactly where differences hide. If you spot a wrong pairing, unmatch it in one click and try again.
Once a period is reconciled and signed off, you can lock it, and any reopening is logged. That helps with minute 0 of the method above: if an opening balance has shifted, the log shows the period was reopened. Read more about bank reconciliation in HelloBooks and the wider bookkeeping features.
FAQs
Why is my reconciliation difference divisible by 9?
Usually because two digits were swapped (like 54 entered as 45) or a decimal point slipped (like $12.00 entered as $120.00). Both produce differences that divide evenly by 9.
What does it mean if the difference is double a transaction?
It usually means that transaction was entered with the wrong sign: money in recorded as money out, or the other way round.
Can there be more than one error?
Yes, and that's why a test can fail on the whole difference. Fix any error you can find, then rerun the tests on what's left.
Should I post a small difference to an expense account?
Not as a habit. If a few cents of rounding is truly unexplained after a proper search, talk to your accountant about how to treat it. Don't let unexplained differences roll from month to month.
How do I stop differences happening in the first place?
Reconcile often, lock reconciled periods, and avoid entering transactions by hand that will also arrive through the bank feed.
The difference is almost always smaller and sillier than it looks at first. Go find it.
Start free, no card needed. Try HelloBooks Free
