Hello Rob Simmonette, there's a reconcile tool within Quickbooks, with which you can find out where the discrepancy is, for example, is there missing transactions, duplicates, etc To do this you click on the cog in the top right of QB and then click on reconcile>it will already have a beginning balance if you added an opening balance it will ask you to put ending date and ending balance at the bank itself we usually recommend doing one month reconcile as its easier to breakdown the point the balance became mismatched that way, once you save that it will ask you to tick all the transactions that should be included( you can check this against you bank statement) it should then show in the figures zero difference. We have included a video here that goes through the process. If it does not show zero difference then that is the point you would look at your statement for missing transactions/duplicates and add missing or remove duplicates. Then go on to the next month and do the same till you are at the current month. Any questions feel free to come back here.