Mortgage Calculator Functions
The purpose of this guide is to describe how to make a mortgage calculator and what functionality we
require.
Please note that mortgage calculators are one of the most searched-for consumer tools online. The
niche is highly competitive. At Mortgage Loan Place, we want to build the best mortgage calculator ever
created. As you know, we are running a huge competition to help us reach this goal!
Required Features and Functionality
The winner of our $10,000 prize must incorporate all of the following features and functionality.
• Calculate mortgage payments. The purpose of the mortgage calculator is to compute the estimated
monthly payment on the mortgage. Download this Excel file to see the formulas for calculating
mortgage payments and read this page on how to find a loan payment. Required Fields – Principal,
Interest Rate, Term. Final Value – Monthly Payment.
• We require input fields for yearly taxes and insurance. The default assumption in these fields should
be 1.5% of property value for property tax, and .5% of property value for homeowner’s insurance. The
default %’s should auto-fill based what the user inputs for principal, interest rate and terms. However,
the user should be able to override the default amounts if they so choose. Required Fields – Taxes and
Insurance.
• Down payment and Private mortgage insurance. Mortgages created with less than a 20% down
payment typically required private mortgage insurance (PMI). Learn how PMI is calculated here and
here. If a user inputs a down payment amount less than 20% of the principal, PMI should be added to
the monthly payment. Assume average PMI costs of $80 for our calculator. Required Fields – Down
Payment and PMI.
• An amortization table or payment graph should be included to help illustrate the increase in equity
and corresponding decrease of principal over the life of the loan. This is required to help users better
understand how their payments will be applied. Here is a good example