**Charlie**Hi,

You can simply pass a calculation value to your payment integration's total field by following this guide: https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field

In your case, you'll need to have a sub-total fields, then get the sum of those and insert or place them inside a Form Calculation widget as the final total, after that you can fetch that final total field in your payment wizard.

Let us know if you need further help on this.

**Charlie**Just to add, the following guides might help you regarding calculations:

Performing calculation using the widget: https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget

Performing calculation using conditional logic: https://www.jotform.com/help/268-How-to-Insert-Text-or-Mathematical-Calculation-into-a-Field-Using-Conditional-Logic

Assigning values to radio button, check boxes, drop down fields for calculation: https://www.jotform.com/help/301-How-to-Assign-Calculation-Value