Why is my GL bank balance different from my reconciliation report?

You may have pulled up your reports with a different date range that's why they're showing mismatch amounts, @evelyn-cardona. Let me share further details bout this.

You'll have to make sure both reports (reconciliation report and balance sheet) share the same report period. This way, you're able to match the data each of them provides. Here's how:

1. Go to the Reports menu.
2. Pull up either the Balance Sheet or Reconciliation report first.
3. Set the appropriate date in the Report period field.
4. Click Run report. Repeat steps to pull up the second report.

I've attached screenshots below that show the last two steps.

Also, I'm adding this article to further guide you in resolving common Balance Sheet issues in QBO: Basic troubleshooting for balance sheets. It includes topics about removing deleted items and matching balance sheets with your register, to name a few.

Let me know in the comments below if you have other concerns about financial reports in QBO. I'm just around to help. Take care always.