XLSJuice

Dynamic from creation based on spreadsheet. Integration for calculators built using XLSJuice spreadsheet to web converter. If you have a working spreadsheet you have a working webpage, this plugins allows you to insert any calculator form inside your WP pages.

You first need to create your calculators at XLSJuice web page, you have a trial account available.

There are a big set of extra plugins that you can use in order to extra functions to your form, some examples:

PDF creation based on word template, with inputs, outputs and any other information needed.
Email sending to you, or your customers, with inputs, outputs and any other information needed (like the pdf from above!).
Data saving. Allow your customers to save their executions, and come back to edit their previouly saved data, download their files…
Mailchimp integration
VTiger integration
Form actions, include dynamic behaviour to your form, like hide/show sections depending on inputs and/or results of the calculator.
Paypal. You can redirect to this payment system in order to turn your quote into a real sale.
Stripe. You can redirect to this payment system in order to turn your quote into a real sale.
…more plugins comming…

also customization available for more complex requirements.