In the past few years, we have covered many useful calculators for WordPress here. The WP Cost Calculator plugin is also worth a look. It helps you create price estimation forms for your site fast. It has 8 elements for you to choose from to build your form.
WP Cost Calculator supports input box, checkbox, range slider, switch box, and other useful elements. It lets you create an unlimited number of calculation forms with your own calculation formula. The PRO version of this plugin supports WooCommerce, Stripe & PayPal integration.
WP Cost Calculator lets you import and export calculators. You can find out more about it here.