How can I put a charge in the payment area that is impossible to unselect and varies depends on what else is selected?

I need to add 8% processing fee to whatever someone selects. So if they select a $200. item, I want to be able to add $16 to that as a "processing fee" field. But it must not variable, depending on the dollar total of items the user selects. And it must not be avoidable / unselectable.

 

Please advise ASAP.

Hello,

Thank you for contacting us.

You can add a tax value to the payment in your form, please , refer to this guide for further help  :

http://www.jotform.com/help/296-How-to-Add-Tax-to-Your-Payment-Form

If you need more help, feel free to contact us.

Thanks.

NO, no, no.
Although this is like tax in how it works, I do NOT want to infer sales tax into this non-taxable item.
I think I figured it out. Please see what I’ve done.
...

Randy thanks for your help, you are right, the Tax Wizard Tool could be used to add the 8% to the payment amount.

Another option would be add a Calculation Wizard, take the amount to pay and then make the calculation to add the 8%.

Both options should work fine.

Thanks.