My bank balance and QB balance are way off

The bank balance and the QB bank balance is often not the same, that is because deposits and checks may not have cleared the bank yet, but may be in QB.

Other than that all you can do is get the past bank statements and go over the bank register against the statement, it is called reconciling if you have not done it in the past.  When you find an entry that is not in one or the other, you need to figure out what it was for and enter it.

Hello,

The bank balance is what QBO reads directly from your banks online access.  The QB balance is the sum of transactions in your QB register.

First thing would be to make sure you don't have transactions waiting to be reviewed and categorized.  Next would be to make sure you go back and all prior months are reconciled.  By reconciling you can make sure that no transactions are missing in QB or duplicated as the bank statement is the truth of what has hit your bank account.