My bank account balances in Quickbooks are very different to the actuals. How can I reset them to the actual bank account balances?

Hi nick14,

Thanks for posting in the Community!

Allow me to provide some information about why QuickBooks bank balance is different with your bank balance. 
 

The QuickBooks balance is affected by all your transactions in the register and the ones you haven't reviewed yet. While the bank balance is solely determined based on the transactions on the register.
 

I'd recommend doing a bank reconciliation to help cross match the transactions in QuickBooks Online versus what you have in your bank statement. That way, you can check if there are duplicate transactions added in QuickBooks Online causing the balance to be different.

To reconcile an account:

1. Click on the Settings icon or Cog wheel icon at the top right.
2. Click on Reconcile.
3. Select a bank account to reconcile.
4. Enter the Ending balance and ending date.
5. Click on Start reconciling.

In the next page, you will see all the transactions added in QuickBooks. Cross-match the transaction with your bank statement making sure everything is accurate and matches.

You can also refer to this link to learn more about bank reconciliation in QBO: Learn the reconcile workflow in QuickBooks.

Keep me posted if you have other banking-related concerns or questions. I'll get back to help you the best that I can.