How to pass a calculation to a payment field ?

I have followed all instructions on http://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field to pass a calculation to the payment field on paypal.

But my paypal widget looks different, instead of 'Get Amount Field' I see 'Suggested amount' (Attached screenshot),

How do I pick the field to take the calculation from on paypal widget?

(My calculation field has already been setup in form)

Thank you 

Hello , 

I've cloned your form and I found the origin for your issue , well we are going to do it in a simple way,please follow the steps below : 

1. First, rename the field from Donation Amount to Calculated Donation Amount and set it as a hidden field : 

2. Now, add the form calculation widget and configure it as the image below, to pass a value from a field to a payment field, it should be a calculation field : 

And rename it from "Calculation" to "Donation Amount" : 

3. Now, you will be able to select the field "Donation Amount" :

You can see my sample form here : 

https://form.jotform.com/53055349992970

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

Regards.

thanks for the detailed answer

You're welcome.

We are here to help you, please , feel free to contact us if you need further assistance.