Custom Calculation Field For Real Estate Website

Hi All,

I need some assistance, I’m busy with a Real Estate website and need to build the following calculation fields..

Minimum Income calculator
Monthly Installment calculator
Increased Installment calculator
Maximum Loan Calculator
Bond status Calculator

I see there is a couple of different Mortgage calculator plugins out there..
I need something that I can use to build a custom field in and maybe supply the formula for the calculation or something…

The site currently runs on my Local Machine via a USB Server, so its not live..