Free Mortgage Loan Calculator is a great value-add for any loan officer or real estate agent looking to provide good-looking, functional, valuable content to readers. The execution of this calculator is superb from the smooth sidebar integration, modal window results and AJAX-based graphs that are incredibly visually appealing. It's a great little application that delivers a lot of value in a user-friendly and well-executed way. Available as copy-and-paste Javascript code, Wordpress plugin and API (for calculator form customization).