Many years ago when interest rates seemed to be declining almost every day, I attempted to determine the exact point I could benefit from refinancing my home mortgage.  At first I search the internet for a mortgage calculator that could aid me in my decision, but to my disappointment I discovered that they all lacked the sophistication necessary to be of much use.

In fact they were so seriously lacking in their complexity that they were nearly financially ineffectual. So after frustratingly realizing I was not going to find what I needed, I decided to build my own mortgage calculators and in 2005 I transferred them to a browser format making them available to the general public. You can try my mortgage calculators at http://www.realestate-calc.com/Mortgage-Calculators.asp.

Determining the economic benefits of refinancing depends on many factors, i.e. 1) what is the rate on your existing loan, 2) what is the current rate at which you can refinance, 3) what will it cost you to refinance, 4) how long do you expect to hold the property hence hold the loan, and 5) what is the time value of money. RealEstate-Calc.com can help guide you through a step by step approach in the application of these variables.

When creating any financial calculator or model there is a tradeoff between complexity and simplicity versus effectual and ineffectual and striking the right balance is the key to being a good analyst. "Mathematical modeling", "manipulation of numeric data" and "displaying numeric results" are all part of an art form! To think otherwise would produce less than superior results.

Most mortgage calculators leave out the ability for the user to adjust for how long they expect to hold the loan and none that I know of allow the user to adjust for the time value of money.  Most do not allow the user to adjust for a mortgage that has already been amortizing for a significant period of time.

These are important variables if you desire more accurate results than the typical mortgage calculator provides.  My mortgage calculators will allow you to adjust for how long you expect to hold a loan (live in the property) and you can adjust for a mortgage that has already been significantly paid down.  You can also consider the effects of making an additional fixed monthly payment to your mortgage.

There are more types of calculators than just mortgage calculators.  There are real estate calculators that can assist you in determining the cost of buying, selling and holding real estate.  They can help you determine the tax consequences of selling a single family or multifamily property which is either investment property or primary residential property.

There are business plan calculators.  These types of calculators are useful for those interested in starting a small business. No business plan can be complete without a financial forecast and numeric framework. Many people considering starting a small business prefer to overlook the utility of a business plan, however those that require funding through more conventional sources often are required to have some type of minimum financial plan in hand.

How do I do it? I combine 20 years of experience as an analyst on Wall Street with the following skill sets: coding in visual basic, yield curve construction, financial statement preparation, business plan development, complex derivative valuation, and risk management. I am a CPA in the state of New York.