Is this done? There’s this field exists in the builder already.

I need a form builder with a calculator with conditional logic options, for my webdesign business, so clients can get an automated quote estimation, while filling in the form and adding the features they need on their website, I know their are free plugins out there like Forminator who have this feature, but to be honest I want a Divi Plugin to do this.

So ends up I kind of developed part of the solution to this problem already with a simple script, where I combine two of our ACF fields to one to post as the title.

<script>
var first = document.getElementById("de_fb_first_name");
var last = document.getElementById("de_fb_last_name");
document.getElementById("myForm").onsubmit = function() {myFunction()};

function myFunction() {
document.getElementById("de_fb_full_name").value = first.value " " last.value;
}

</script>

So for your particular idea, to add two variables, you could re-write the same script as the following:
<script>
var v1 = document.getElementById("[INSERT ACF ID NAME]");
var v2 = document.getElementById("[INSERT ACF ID NAME]");
document.getElementById("myForm").onsubmit = function() {myFunction()};

function myFunction() {
document.write(v1 v2);
}

</script>

And it would show up on the next page.

I would assume that the developers here would simply have to add this to the PHP backend, with the above script or something similar to then allow the user to choose the OPERATION (Addition, Multiplication, etc.) the number of variables (2, 3, 4 things invovled, etc.) and then a specific option on where to put the output - a new page or in another input field?

I hope that helped.

Definitely a useful feature - for my type of clients who want an advanced estimate form on their website. A way to calculate and create a total Estimate after the user completes the form. Right now I'm using fluent forms… happy with it but would prefer to have your suite of divi plugins. 🙂

Here’s a sample from another plugin…

https://stylemixthemes.com/cost-calculator/custom-totals/

Make it something you can use inside or outside a form. Enable the starting value to optionally use a field so you can chain it and do multiple step calculations by duplicating the module and adding a new calculation.