Mortgage Calculator App

WPF

In order to get a better understanding of Windows Presentation Foundation (WPF) I've decided to dive right in.

A while back I had created a Mortgage Calculator in C# .NET 1.2 as a Windows Form Application:

However, the GUI implementation left something to be desired. I wanted to avoid using modal forms. Instead the UI needed to be isolated to one window. While a trivial task, adding 2 panels to a form and switching the visible property seemed like a hack and annoying to maintain. Other suggestions seemed to suffer from the same basic problems.

Enter WPF. WPF uses DirectX which pipes all the UI processing to the GPU. This saves the CPU from wasting calculations. The following post on stackoverflow.com has a fairly succinct break down of it.

Instead of generating the GUI with pure code as Windows Form Application does, WPF uses Extensible Application Markup Language (XAML). XAML is an XML based user interface markup language. It's values define UI elements, data binding, events and more.

Using WPF, implementing a form with multiple GUI states doesn't feel as clumsy. Also, databinding takes away much of the coding I used to encounter with loading, validating and updating values in the database.

Mortgage Calculator

The Mortgage Calculator is intended to give your average everyday landlord/amateur investor a rough estimate of what his properties vital stats will be month by month in the amortization schedule.

A problem with most Mortgage Calculators, especially at Real Estate or Mortgage websites, is their lack of data. In particular, leaving out Tax and Insurance from the monthly payment might give someone unrealistic expectations of their out of pocket costs.

Mortgagecalculator.org includes tax but leaves out insurance and Association dues.

As an example lets pull up a listing from http://mihome.mobi/:

Plugging this information into MortgageCalculator.org we get:

$24,375.00 doesn't tell us much. Did the property tax increase over the 30 year amortization or is this a fixed dollar amount every year?

$24,375 breaks down to $812.50 a year.

Again we have no idea about Insurance or Association Dues.

When we scroll down in the listing we find that the tax was underestimated.

Perhaps we had the wrong percentage? Yes, but home values used to calculate property tax themselves are figured out by a city tax assessors who's valuations can differ from the current market value. Simply stated the only tax rate that matters is the current dollar amount listed, which in this case is $582.50 higher.

Principal and Interest Payment: $348.93
Tax: $1,395 / 12 = $116.25
Insurance: $500 / 12 = $41.67
Association Dues: $246

Total Payment: $752.85

Almost double what MortgageCalculator.org showed!

What about the changes in tax, insurance and other costs? If the total payment now is $752.85 it will most certainly become more expensive in the future.

I designed Mortgage Calculator to address 3 main areas where details were lacking:

1. Total cost of owning and maintaining the house.
2. Future appreciation of all costs.
3. Rental stats.

In the amortization schedule I would want to track the following:

• Principal
• Interest
• Extra Payments
• Balance
• Home Value
• Tax
• Insurance
• Association Dues
• Maintenance
• Total Monthly Cost
• Equity
• Loan To Value
• Rental Income
• Cash Flow

On top of this I would want to assign appreciation rates to the following values:

• Tax
• Insurance
• Association Dues
• Maintenance
• Rent
• Home Value

In our next post we will be dealing with creation of the Database.


Download the Code Here