Is it possible to take only the postal code portion of the address field to use it in calculations?

For Example if I have the full address in one field separated by commas.

How can I just select the post code part to use into the distance calculator?

The Post code is at the end of the field, if it helps I can put the Post code at the start

Unfortunately, I don't think this is possible using only the form builder.
I think you need to use the full source code of your form and a custom script in order to do this.

However, I would like to ask if you have checked our driving distance widget? This widget can calculate a distance between two locations. Would this widget work for your needs?

Can I auto update the field of the start and end of the Driving distance widget? This will be a post code field already filled on the form earlier!

Unfortunately, that's also not possible because the widget is rendered in an iframe which won't allow to auto-populate the starting city and destination city fields using another value's field. They would need to be entered manually.

Let us know if you have further questions.