Check your opening balance first. If the opening balance in your accounting software doesn’t match the ending balance from last month’s bank statement, nothing else will add up correctly. In QuickBooks Online, this can get thrown off when someone modifies or deletes a transaction that was previously reconciled. Fix the opening balance before investigating anything else.

If the opening balance is correct, look at the size of your difference. When a discrepancy is divisible by 9, you likely have transposed numbers somewhere. You entered $54 when it should have been $45, or $1,320 instead of $1,230. This is one of the most common data entry errors and the divisible-by-9 pattern helps you spot it quickly.

Duplicate transactions are another frequent culprit. Bank feeds sometimes create duplicates when you also enter transactions manually. Look for transactions with the same amount around the same date. The flip side is missing transactions. Bank fees, interest charges, automatic payments, and ATM withdrawals are easy to miss if they don’t come through the bank feed properly or if someone forgot to record a check.

Date issues cause problems around month-end. A transaction dated December 31 in your books but January 2 on the bank statement will throw off both months. Compare dates carefully, especially for transactions near the cutoff.

If you have a small difference and you’ve already spent 30 minutes searching, consider whether your time is worth more than the discrepancy. Some businesses create a reconciliation adjustment for a $3 difference rather than spending hours hunting. This isn’t ideal practice, but it’s sometimes the practical choice.

For larger differences, go line by line. Print your bank statement and check off each transaction against your books. Whatever doesn’t have a match on either side is your problem. This is tedious but effective when other methods fail.

Persistent reconciliation problems usually point to something systemic. Inconsistent data entry, multiple people recording transactions without coordination, or bank feeds that aren’t configured correctly. A Mid-Missouri bookkeeper can help identify whether you have a one-time discrepancy or a recurring process issue that needs addressing.

When the discrepancy has been carried forward for multiple months or you’ve spent hours without progress, professional help makes sense. Old reconciliation issues get harder to fix the longer they sit because they require adjusting previously reconciled periods. Bookkeeping cleanup often starts with untangling exactly this kind of problem so the monthly books can move forward on solid footing.