Mortgage Payment Calculator

• This app calculates mortage rates reactively by taking in user inputs
• These inputs include cost of the mortgage, downpayment percentage, interest rate and term of the mortgage loan
• It does not, however, calculate and provide estimates mortgage insurance, real estate taxes, or homeowner's insurance

• Slider for downpayment percentage
• Slider for term of loan payment
• Instant calculations and onscreen explanations (along with amortization equation)
• App is set in showcase mode so users can see code

• The application is instantly calculating the monthly payment via the following formula:
  \[ (\text{Principal})\frac{(\text{Interest rate})(1+\text{interest rate})^\text{Term}}{(1+\text{interest rate})^\text{Term}-1} \]
  
  • Principal refers to the amount left after the downpayment (which is usually expressed as a percentage of the cost)
  • Term is the amount of time to pay the mortgage, usually 15 to 30 years

• For example, for a house with the following parameters…

cost=405000
downpayment=20
interest=3
term=15

…gets evaluated through the following formula:

value = (cost) * (1 - downpayment/100) * (interest/1200) * ((1 + interest/1200)^(term * 
    12))/((1 + interest/1200)^(term * 12) - 1)

…resulting in a mortgage payment of…

[1] 2237.485

So why you want this app?

• So easy and fun to use!
• Results are instant and non-cumbersome!
• Instructions are displayed onscreen!