I found these on the web through different source and I am not sure how much use they will be or the simplest or you to use, but don’t feel obligated to use any services advertised on this website.
Simple mortgage calculator from Kim Komando – http://amortizationloancalculator.net/index.php
Various mortgage calculators – http://www.calculators4mortgages.com/
Determination to refinance an existing mortgage – http://www.bills.com/calculator-mortgage/
Domania.com offers calculators an recent home sales in your neighborhood – http://www.domania.com/Calculator/default.aspx
Helpful tips and mortgage calculator – http://www.mtgprofessor.com/home.aspx
Lending tree (careful – you may get alot of ads) – http://www.lendingtree.com/mortgage-loans/calculators/loan-payment-calculator/
References to products and services are not a specific endorsement, but the user must perform their due diligence and investigate whether the product or service is right for them. I welcome any or all comments that would help others.