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    How to collect custom amount invoiced payments through PayPal

    Asked by EOTW on January 07, 2017 at 10:25 AM

    I would like customers to be able to pay their invoices online.  They receive their invoice by printed mail.

    I need to add a surcharge to the invoice if they pay online.

    So i need them to enter the amount of the invoice, and then I need to automatically add a service fee, to come to a total that they agree to pay via paypal.

    How would I do this?

    Thank you

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    Answered by Boris on January 07, 2017 at 12:10 PM

    You can do this by (1) having a Number field on your form where users would enter their amount manually, (2) having a Form Calculation where you would calculate a total amount based on what they entered on the Number field, and then (3) pass this calculated amount to PayPal for payment.

    Step 1: We add a Number field.

    Step 2: We create a form calculation, and set it to calculate the number field plus our service fee.


    Step 3: We pass the calculated total to the payment field:


    Please see the following demo form of this kind of setup:


    Please try it out, and let us know should you need further assistance.