Paypal : How to pass a calculation to a payment field ?

I see how to select different items but I need to know how to select more than one of the same item and total it up.   Thanks!

Hi,

You should have calculation in your form, you can find further help in this guide : 

http://www.jotform.com/help/259-How-to-perform-calculation-in-the-form

And you can pass the calculated value to a payment field, refer to this guide : 

http://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field

You will be able to calculate to total and then pass it to the payment field, and this will be your total to pay.

I hope that helps.

Regards.